Enceladus shows little sodium leaving scientists questioning existence of underground ocean

One of Saturn’s moons, Enceladus, appears to be missing some sodium. The new observations made at the W. M. Keck Observatory suggest that the plumes of gas and ice seen exploding from the moon are not fueled by geysers erupting from a salty ocean just beneath Enceladus’ surface. The conclusion has left scientists uncertain about the tiny moon’s interior.

“We really expected to see sodium in the data giving evidence right then and there of a possible ocean on Enceladus,” said astronomer Mike Brown of the California Institute of Technology. To the astronomers’ surprise, no spectral feature appeared in the data.

The team of international astronomers, led by Nick Schneider of the University of Colorado, used the High Resolution Echelle Spectrometer, or HIRES, at Keck Observatory to analyze the sunlight reflected by Enceladus. The calculated upper limit of sodium present in the moon’s vapor plume was 30 times lower than expected, the astronomers report in the June 25 Nature. 

Observing little to no sodium in the plume vapor and ice grains erupting from the southern pole of Enceladus is “quite surprising” because other, less active bodies in the Solar System have sodium signatures that are much easier to distinguish, said planetary scientist John Spencer of the Southwest Research Institute in Boulder, Co., who was not involved in the study.

Sodium atoms are among the most easily detected and most common elements in the Solar System. Their non-existence in the Enceladus’ jets suggests the moon is very different from Jupiter’s moons Io and Europa, the Moon and Mercury, which all show sodium signatures in their thin atmospheres, Brown added.

The vapor and ice particles found in the jets are also thought to be the source of Saturn’s outermost ‘E’ ring. The jets, and salt in the ring, could therefore be coming from a much deeper, salt-based ocean. Brown said that deep caverns might allow water to evaporate slowly, which would mean it would contain little sodium—much like water evaporating from Earth’s oceans. The vapor could turn into a jet because it would leak out of fractures in the moon’s icy crust and then into the vacuum of space.

The scenario is possible, but the new observations could also mean that the low-salt vapor escaping from Enceladus comes from evaporation of a low-salt, liquid reservoir or from warm ice sublimation—the transition from solid to gas with no liquid phase, Brown explained. The plume could also originate from the decomposition of molecular cages called clathrates, which might release small amounts of sodium.

“In essence, we still don’t understand the origin of the ice and vapor jets and therefore how the salt particles get into space,” he added.

Enceladus is a “very different beast,” and theorists need to do more work to understand how vapor and ice grains form inside Enceladus and then get out to the ‘E’ ring, Spencer said.

“Basically, this result shows we don’t really know what’s going on within this little moon. It also shows us that ground-based telescopes, such as Keck, are essential to Solar System studies,” Brown said. “Now we astronomers have to put our heads together to figure out how we are going to learn more about Enceladus.”

The W. M. Keck Observatory operates twin 10-meter optical/infrared telescopes on the summit of Mauna Kea on the island of Hawai’i. The two telescopes feature a suite of advanced instrumentation including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and a world-leading laser-guide-star adaptive optics system. The Observatory is a scientific partnership of the California Institute of Technology, the University of California and NASA. For more information please call 808.881.3827 or visit http://www.keckobservatory.org.

Exoplanet’s titled orbit challenges theories of planet formation

An international team of astronomers has discovered an exoplanet whose orbit is steeply titled from the plane of the star’s equator, a finding that contradicts theories about how planetary systems form.

The new observations conducted at the W. M. Keck Observatory in Hawaii provide a clear, solid measurement of the planet’s distinctive tilt, determining the angle of the orbit to be about 37 degrees from the star’s equator. The results appear in the online edition of the Astrophysical Journal and will be published in an upcoming August issue.

Astronomers discovered the planet, called XO-3b, because it passes directly in front of the star as seen from Earth - an event called a transit - thus causing a slight dimming of the star’s light. That dimming can be detected with a powerful telescope connected to a highly sensitive light meter, or photometer. Of the more than 350 exoplanets discovered so far, fewer than two dozen have been discovered through this transit method.

Detecting the planet itself was relatively easy, as it dimmed the star’s light by about one percent. But to go one step further and measure the angle of its orbit, even with such powerful tools, means that “we have to be sneaky about it,” said physicist and the paper’s lead author Joshua Winn of the Massachusetts Institute of Technology in Cambridge, Mass.

He explained that if a planet crosses the star’s disk at an angle relative to the star’s rotation, it causes a distinctive pattern that changes the overall color of the star, as measured by a highly sensitive spectrograph. In this study, astronomers John Asher Johnson of the University of Hawaii and Andrew Howard of the University of California Berkeley (UCB) used the Keck I telescope’s High Resolution Echelle Spectrometer, or HIRES, to confirm hints of such a spectral signature, which another team observed but could not verify last year.

Observing a misalignment of the planet’s orbit relative to the star’s equator is a “remarkable result,” and completely contradicts simple theories of planet formation, said astronomer and paper coauthor Geoff Marcy of UCB.

“In all models of planet formation, a young star is surrounded by a flattened disk of gas and dust, like a fried egg with the yellow yolk, the star, in the middle and the white, the gas and dust, extending outward from the equator of the ‘yolk’,” he explained.

The planets form by collecting the dust and gas together within that disk. The theories naturally explain how the planets in the Solar System reside in a flat plane that slices through the equator of the Sun. Other planetary systems show a similar architecture.

“What is shocking about this planetary system is that the planet orbits in a plane that is grossly misaligned with its star’s equator,” Marcy said.

XO-3b, is about 13 times as massive as Jupiter, yet orbits its star with a period, or “year,” of just 3.5 days. Jupiter, by contrast, takes almost 12 years to make one orbit. The planet is considered a “hot Jupiter,” meaning it resembles the Solar System’s largest planet yet is much hotter due to its proximity to its parent star.

The planet, as with all hot Jupiters, most likely didn’t form at its current orbit, but rather formed much farther out from the star, then migrated inward to its present position. Planet formation theory suggests the gravitational attraction of other planets as well as debris in the disk might tug on planets, slightly disrupting their orbit. Close encounters between or among planets, however, has enough force to significantly change the planet’s trajectory.

In the case of XO-3b, it seems “some other planet gravitationally yanked on this poor planet, jerking it out of its original circular orbit,” Marcy said. It “suffered from a gravitational close encounter. It survived, but was left in a wacky orbit.”

Astronomers are interested in exploring exoplanets, especially oddballs such as XO-3b, to help refine theories of planetary formation and to understand the kinds of variations that may be possible in the Universe. Astronomers want to “see how the dice get rolled in other planetary systems,” Winn said.

NASA’s recently launched Kepler Mission will help astronomers discover increasing numbers of exoplanets, he explained. The Keck telescopes will then be used to follow-up the space-based observations to learn more about the planets’ masses and orbits.

By discovering and observing more oddball exoplanets, astronomers will determine how often planets suffer from close encounters. And, if a large number of exoplanets are observed to have titled orbits, scientists might be able to conclude that close encounters are common during the young lives of planets, Marcy said.

The XO-3b work was funded by the NASA Origins program, an NSF postdoctoral fellowship and World Premier International Research Center Initiative.

The W. M. Keck Observatory operates twin 10-meter optical/infrared telescopes on the summit of Mauna Kea on the island of Hawai’i. The two telescopes feature a suite of advanced instrumentation including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and a world-leading laser-guide-star adaptive optics system. The Observatory is a scientific partnership of the California Institute of Technology, the University of California and NASA. For more information please call 808.881.3827 or visit http://www.keckobservatory.org.

Keck Laser Helps Astronomers Probe the Nature of Massive Galaxies in the Early Universe

PASADENA, Calif.—Astronomers using the W. M. Keck Observatory have discovered distant galaxies as massive as the Milky Way yet ten to 1000 times more compact. The new results, announced June 9 at the 214th American Astronomical Society meeting in Pasadena, provide astronomers with surprising clues about early star and galaxy formation at a time when the Universe was just a few billion years old.

“The shapes of these galaxies tell us that it is not reasonable to expect they could occur from mergers. Instead, the kind of disks we’re seeing and the constituent stars seemed to have formed all at once, directly from the gas. In the old lingo, this is monolithic galaxy formation,” said astronomer Alan Stockton of the University of Hawai’i.

He and his colleagues Dr. Gabriela Canalizo of the University of California, Riverside and Dr. Elizabeth McGrath of the University of California, Santa Cruz used the Keck II telescope and its Laser Guide Star Adaptive Optics, or LGSAO, to image radio galaxies and quasars that are roughly 11 billion light years from Earth.

The Keck LGSAO system uses a powerful laser to excite sodium atoms in the upper atmosphere so that they emit light and appear as an artificial star. Astronomers use this artificial starlight to analyze how the atmosphere is distorting incoming light from their target astronomical sources. The distortion can then be corrected using a compensating distortion in a deformable mirror in the adaptive optics system.

From these AO-corrected observations of distant galaxies, Stockton and his colleagues could model the detailed structures of their target galaxies, which are quite unlike those of massive galaxies in the present-day Universe. The team found the objects had masses that were a hundred billion times the mass of the Sun, yet were compact and have diameters of roughly 3,000 to 15,000 light years. By comparison, the diameter of the Milky Way is 100,000 light years, yet it has a mass of about 500 billion solar masses.

Teams using the Hubble Space Telescope have also found that high redshift galaxies tend to be more compact than astronomers expected. Stockton said his team was able to obtain near-infrared images from the ground that were almost two times sharper than those they could obtain with the Hubble Space Telescope at similar wavelengths. These Keck LGSAO images allow not only the measurement of characteristic sizes of the distant galaxies, but also more detailed properties of the light distribution that may give clues to formation processes.

For example, Stockton’s team imaged a field of five galaxies two of which show a tidal tail (Fig. 2) that would be indistinguishable with Hubble. “The tail, however, can only form if the galaxies we observe were disk galaxies,” Stockton said. “This Keck data gives us further evidence of that conclusion.”

Astronomers expected that distant galaxies might be disk galaxies and would be more compact than today’s galaxies. They did not expect the galaxies to be as dense as Stockton’s observations indicate, and researchers have not yet identified objects in the local Universe that resemble these compact disk galaxies. This is surprising because dense, disk-like objects are like cannon balls and are therefore not easily destroyed by collisions, meaning some should survive today.

“It might therefore be possible that these disk galaxies have instead become the cores of today’s galaxies,” Stockton said.

The data cannot yet answer this or other questions about the morphology and evolution of these two billion-year-old galaxies. Stockton said that he is currently trying to obtain clearer spectral data of the distant galaxies to determine how fast their constituent stars are moving about their centers—this will enable astronomers to independently determine the galaxies’ masses. His team is also currently looking for examples of very compact galaxies that have survived to a time when the Universe was half its present age, about seven billion years old. It will be possible to obtain much more detailed observations of such galaxies, which may lead to a better physical understanding of these objects. Observations to find disk galaxies at more distant redshifts will also be done to determine if disk galaxies exist in the very early Universe, Stockton said.

The Keck II telescope and its LGSAO are operated by the W. M. Keck Observatory, which manages twin ten-meter optical/infrared telescopes on the summit of Mauna Kea on the island of Hawai’i. The two telescopes feature a suite of advanced instrumentation including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and a world-leading laser-guide-star adaptive optics system. The Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA. For information please call 808.885.7887 or visit http://www.keckobservatory.org.

This research was supported in part by the National Science Foundation, under grant AST 03-07335.

Berkeley Astronomers Lift Shroud on Dark Gamma Ray Bursts

PASADENA, Calif.—Astronomers using the Keck telescopes may have solved the mystery of dark gamma ray bursts—intense flashes of X-ray and gamma-ray radiation that have little to no optical signature. The observations have allowed the astronomers to peer through celestial gas and dust to reveal star formation and stellar death in the dusty corners of otherwise dust-free galaxies.

“We have compelling evidence that a large percentage of star formation in the early Universe is actually hidden by dust, even inside galaxies that do not appear dusty,” astronomer Daniel Perley of the University of California, Berkeley announced June 8, 2009 at the 214th American Astronomical Society meeting in Pasadena, Calif.

Long-duration gamma-ray bursts, the most brilliant flashes of light in the Universe, are thought to originate from the explosion of massive stars. These events create two pencil-like beams of light, akin to lighthouse beacons, bright enough to be seen from as far away as 13 billion light years, which is near the edge of the observable Universe. Most gamma-ray bursts continue to shine brightly in optical light for many hours after the gamma-ray emission subsides, a phenomenon known as an ‘optical afterglow’. Yet, events with little or no detectable visible light, dubbed “dark GRBs,” have puzzled astronomers.

Some have suggested that these GRBs are so far away, and thus at such high redshift, that their optical afterglow is shifted out of the visible wavelengths and into the infrared. The new observations, however, support one other prevailing hypothesis for the existence of dark gamma ray bursts— that dust obscures the visible wavelengths of the gamma ray bursts in galaxies at less extreme distances (less than about 12.9 billion light years from Earth).

“The Perley and Bloom work is a very significant result,” said Wendy Freedman, director of the Carnegie Observatories in Pasadena, Calif. who was not involved in the research. She explained that GRBs have excited the astronomical community since their detection in the 1960s. This study is “fundamental,” she explained, because it provides information about the nature of GRBs in the early Universe. It also provides important information about the formation rate of stars when the Universe was merely 700 million years old, she added.

To draw these conclusions, the team first used the 60-inch Palomar telescope to conduct follow-up observations of 29 bursts discovered by NASA’s Swift gamma-ray satellite, 14 of which were classified as dark. The astronomers then used the Keck I telescope to look for the host galaxies of “dark” GRBs. For 11 of these 14 dark bursts, the team successfully detected a distant galaxy hosting the explosion. The remaining three bursts had faint optical counterparts.

Perley said the results indicate that none of these bursts had come from the most distant regions of the Universe since at distances greater than 12.9 billion light years the optical light would be shifted into the infrared due to the expansion of the Universe. The astronomers’ sample lacks these very high redshift events, which indicates that extremely distant explosions cannot comprise more than a few percent of all gamma-ray bursts, Perley said.

Still, such distant bursts are known to exist. Two months ago a gamma ray burst at a distance of 13.1 billion light years was discovered. Combining information from this event with the rest of the sample, the team now estimates that the fraction of high redshift GRBs is between 0.2 and seven percent.

In this study, because dim optical signatures where identified and none of the 14 bursts in the survey appear to be at a distance of more than 13 billion light years, the astronomers can conclude that the optical dimness of the bursts is due to dust inside the host galaxy. The dust absorbs light from the afterglow before it escapes. But, the starlight shows no recognizable dust signatures, which indicates that the dust may be clumped in patches or clouds where it is difficult to detect.

Consequently, there could be much more dust than has been suspected as the result of measurements using other techniques. Perley said that dark gamma-ray bursts could therefore provide a complementary way of answering the question of how much star formation is going on inside galaxies in the early Universe. The data indicate that the star formation rate in the early Universe was not as intense as previously thought. More research needs to be done to confirm this conclusion.

The team has submitted a paper about the study to The Astronomical Journal.

The W. M. Keck Observatory operates twin 10-meter optical/infrared telescopes on the summit of Mauna Kea on the island of Hawai’i. The two telescopes feature a suite of advanced instrumentation including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and a world-leading laser-guide-star adaptive optics system. The Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA. For information please call 808.885.7887 or visit http://www.keckobservatory.org.

The Swift mission, equipped with a gamma-ray detector and X-ray, ultraviolet and optical telescopes, is operated by NASA’s Goddard Spaceflight Center.

Mysterious Space Blob Discovered at Cosmic Dawn

Astronomers using a suite of telescopes including the W. M. Keck Observatory have discovered a giant gas object that may be one of the earliest ancestors of a forming galaxy. This object, dubbed an extended Lyman-Alpha blob and identified as Himiko, sits nearly 13 billion light years from Earth and spans 55 thousand light years, a record for that early point in time.

“Measuring the distance to this object with Keck’s instrumentation was fundamental to making this discovery,” says Taft Armandroff, director of the Keck Observatory. “The observations show that this gigantic gaseous object formed when the Universe was only about 800 million years old, a time when astronomers have not expected to see objects like these.”

In fact, astronomer Masami Ouchi, a fellow at the Observatories of the Carnegie Institution, was not sure of what he and his colleagues were observing when they first spotted Himiko. Even with data from the world’s best telescopes, the Lyman-Alpha blob is one of the most distant objects ever found. Its distance does not easily allow researchers to understand its physical origins. The object could therefore be ionized gas powered by a super-massive black hole, a primordial galaxy with large gas accretion, a collision of two large young galaxies, super wind from intensive star formation or a single giant galaxy with a large mass of about 40 billion Suns, says Ouchi, who led the astronomers from the U.S., Japan and the United Kingdom in discovering Himiko.

“I never imagined that such a large object could exist at this early stage of the Universe’s history,” Ouchi says. “I am surprised by this discovery because according to Big Bang cosmology, small objects form first and then merge to produce larger systems.” This object spans 55 thousand light years, which roughly compares to the radius of the Milky Way. Yet, it exists at a time when the age of the Universe was only six percent of the age of today’s Universe, Ouchi explains.

He and his colleagues first discovered Himiko in the constellation Cetus using the Subaru telescope. The object was among 207 distant galaxy candidates. But it seemed extraordinarily large and bright to be far away. The team, therefore, hesitated to spend their “precious telescope time” taking spectra of this “weird candidate” because the object might be a foreground interloper contaminating the galaxy sample, Ouchi says. The astronomers decided to take the spectra anyway using the Keck II telescope and its DEep Imaging Multi-Object Spectrograph and also Carnegie’s Magellan/IMACS instrumentation and were then able to measure the distance to Himiko.

Most of the extended Lyman-Alpha blobs discovered so far sit at distances when the Universe was two to three billion years old. But, the data show Himiko is located at the re-ionization epoch, which occurred between about 200 million and one billion years after the Big Bang and which is one of the earliest observable points in the history of the Universe. To better understand the re-ionization epoch, astronomers search for characteristic hydrogen signatures released when the region’s ionized gas clouds scatter light in a specific way. Theoretical studies suggest that the first stars and galaxies formed from neutral hydrogen atoms and that these objects subsequently emitted ultraviolet photons re-ionizing the Universe.

Himiko’s spectra clearly exhibited the re-ionization epoch characteristic hydrogen signature indicating that the object was actually at a distance of 12.9 billion light years, Ouchi says. The research appears in the May 10 issue of The Astrophysical Journal. 

Data taken with NASA’s infrared Spitzer Space Telescope, the United Kingdom Infrared Telescope, radio data from the Very Large Array and X-ray imaging from the XMM-Newton satellite allowed astronomers to estimate Himiko’s visible mass and its star formation rate. The astronomers have also begun investigating whether the object contains a central, active super-massive black hole at its core.

Himiko’s existence is puzzling, however, because if it marks a new class of objects that are ancestors of today’s galaxies, astronomers should have already found smaller ones in distant regions, says team member Alan Dressler also of Carnegie. But this object is currently one-of-a-kind. Its discovery therefore makes it hard to fit the object into the prevailing model of how normal galaxies were assembled.

The team’s research was funded by the NASA through an award issued by JPL/Caltech, the Department of Energy, and the Carnegie Institution. The result is based in part on data collected at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA; Subaru Telescope, which is operated by the National Astronomical Observatory of Japan; the Spitzer Telescope, managed by JPL for NASA; the Magellan telescopes operated by a consortium consisting of the Carnegie Institution, Harvard University, MIT, the University of Michigan, and the University of Arizona; and the United Kingdom Infrared Telescope, which is operated by the Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the UK.

Cluster Heavyweights Caught in Cosmic Traffic Jam

Astronomers have recently identified the Universe’s most crowded cosmic free-way, where monster galaxy clusters are slamming together in one of the largest collisions ever recorded. Pinpointing such a pile-up required data from three of the world’s best telescopes, and the discovery now provides scientists with a chance to watch what happens when some of the Universe’s largest objects collide. 

A team of astronomers from the University of Hawai’i used the W. M. Keck Observatory on Mauna Kea, Hawai’i, and the space-based Chandra X-ray Observatory and Hubble Space Telescope, both NASA missions, to collect their data. The team then calculated the three-dimensional geometry and motion in the system MACSJ0717.5+3745, or MACSJ0717 for short, which is located about 5.4 billion light years from Earth in the direction of the Hydra constellation.

The researchers’ new data shows that four separate galaxy clusters are involved in a triple collision. Galaxy clusters are the largest objects bound by gravity in the Universe, and it is the first time astronomers have ever observed such a massive merger. Only by observing such violent collisions can astronomers better understand how clusters grow, says the team’s lead researcher Cheng-Jiun Ma of the University of Hawai’i.

To make such observations, the astronomers used the Keck II telescope and its DEIMOS instrument from 2004 to 2008, as well as the Hubble Space Telescope in 2004, as part of an ongoing research project to learn more about cluster and galaxy evolution.

Taking spectroscopic data is the only way to measure galaxy velocities along the line of sight. This data adds the crucial third dimension to what the team can learn about the dynamics of a large cluster from its gas and galaxy densities, says team member Harald Ebeling, also of the University of Hawai’i. The DEIMOS instrument’s large field of view and Keck’s massive light gathering power make the instrument and telescope the only research tool that can survey a structure as large as MACSJ0717 in a reasonable amount of time.

“After all, this cluster is at a few billions of light years from Earth, meaning it takes one to two hours even with Keck to measure reliable radial velocities for cluster galaxies,” Ebeling notes.

The optical data provides information about the radial motion and density of galaxies. The team then combined the Hubble and Keck data with information taken with the Chandra X-ray Observatory to determine the three-dimensional geometry and motion in the system and how that motion affects the collisions.

The data revealed a large, hot region located where a long stream of galaxies and gas—known as a filament—runs into MACSJ0717. The filament extends 13 million light years and pours gas and galaxies into the system like cars exiting a crowded interstate into a full parking lot. This influx of matter causes one collision after another.

Each of the collisions releases energy in the form of heat. MACSJ0717 therefore has one of the highest temperatures ever seen in such a system, Ma explains.

The filament leading into MACSJ0717 had been previously discovered. But the new results show that it is the source of the cluster collisions. The evidence is two-fold. First, by comparing the position of the gas and clusters of galaxies, the researchers tracked the direction of clusters’ motions, which matched the orientation of the filament in most cases. Second, the large hot region in MACSJ0717 is located where the filament intersects the cluster, suggesting ongoing impacts.

“MACSJ0717 shows how giant galaxy clusters interact with their environment on scales of many millions of light years,” Ebeling says. “This is a wonderful system for studying how clusters grow as material falls into them along the filaments.”

Computer simulations show that the most massive galaxy clusters should grow in regions where large-scale filaments of intergalactic gas, galaxies, and dark matter intersect, and material falls inward along the filaments.

“It’s exciting that the data we get from MACSJ0717 appear to beautifully match the scenario depicted in the simulations,” Ma adds.

In the future, he and his colleagues want to use even deeper X-ray data to measure the temperature of gas over the full 13 million light year extent of the filament to learn more about how structure in the Universe grows and evolves.

NASA’s Marshall Space Flight Center in Huntsville, Ala., manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra’s science and flight operations from Cambridge, Mass. NASA Goddard Space Flight Center in Greenbelt, MD performs the daily orbital operations, servicing mission development, and overall management of the Hubble Program. The Space Telescope Science Institute (STScI) in Baltimore, MD develops and executes Hubble’s scientific program and is managed by the Association of Universities for Research in Astronomy (AURA) under contract to NASA.

The W. M. Keck Observatory operates twin 10-meter optical/infrared telescopes on the summit of Mauna Kea on the island of Hawai’i. The two telescopes feature a suite of advanced instrumentation including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectrographs and a world-leading laser-guide-star adaptive optics system. The Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California and NASA. For information please call 808.885.7887 or visit www.keckobservatory.org.

Keck and Kepler team up to find other Earths

Kamuela, Hawaii—  For nearly a decade, Cal-Berkeley astronomer Geoff Marcy and his colleagues have been using the W. M. Keck telescopes to discover giant planets orbiting distant stars. Now, with the successful launch of NASA’s Kepler mission, they will be using Keck I’s ten-meter astronomical eye to discover distant Earths. Kepler will pick out Earth-like candidates. Keck will then zero in on them and determine, with certainty, if they are at all similar to our home planet.

“Keck and NASA have a long-standing partnership to push astronomy research to its fullest potential. This Keck-Kepler collaboration gives that partnership a compelling new scientific focus,” said Taft Armandroff, the Director of Keck Observatory headquartered in Kamuela, HI.

Kepler was launched from NASA’s Kennedy Space Center last Friday.  Aboard the spacecraft is an 84-megapixel camera that will focus on a single region of the sky and snap repeated images of 100,000 stars looking for those that dim periodically. By studying the stars’ episodic decreases in starlight, astronomers will be able to determine the diameter of the object that passes in front of the star, blocks its light and causes the dimming.

“Kepler does not tell astronomers with certainty if the object taking a bite out of the starlight is a planet or another star. That is where Keck plays a crucial role to the Kepler mission,” said Marcy, a frequent Keck user and Kepler mission co-investigator. He, along with a large international planet-hunting team, has discovered nearly half of the 300-plus known planets outside the Solar System.

Astronomers call the objects Kepler detects transits because from the telescope’s perspective the planet candidate seems to eclipse its parent star’s light. The phenomenon is similar to the Moon eclipsing the Sun during a total solar eclipse. But a distant planet eclipsing its parent star will only block a small fraction, 1/10,000, of the star’s light. The Moon, by contrast, blocks nearly all of the Sun’s light in a total solar eclipse.

In the Kepler-Keck duo, once Kepler team members find an Earth candidate and determine as best they can that they’re not looking at two stars orbiting each other, they will hand the object off to Marcy and his colleagues. The team will use Keck I telescope and its instrument HIRES, the High Resolution Spectrometer, to monitor how the light coming from the parent star changes as the planet candidate orbits.

HIRES is an instrument that spreads light collected from the telescope mirrors into its component wavelengths or colors. This is called a spectrum. When the planet candidate orbits around the back of the star, its gravity will ever so slightly pull on the star causing the star’s spectrum to shift toward redder wavelengths. When the planet comes around in its orbit to cross the face of the star, it will pull the star in the other direction, and the star’s spectrum will shift toward bluer wavelengths. HIRES will detect these shifts and give astronomers the star’s radial velocity, or the speed at which the star moves toward or away from Earth. Based on this speed, Marcy and his team will be able to calculate the mass of planet candidate.

“Keck’s HIRES is the only game in town that can measure spectral shifts caused by an Earth-sized planet. No other telescope-spectrograph combination is powerful enough,” Marcy said. “That is why NASA is really heavily dependent on the Keck telescopes right now.”

Calculating the planet candidate’s mass is important because it tells astronomers whether a planet or another star is eclipsing the parent star. If the object turns out to be a planet, Marcy and his team can then use the Keck-calculated mass and Kepler-calculated diameter to determine the planet’s density. “In a sense it’s as if we are taking the planets and dunking them in a bathtub to see if they float. A rocky planet like Earth would sink,” Marcy said. Earth has a density of about five grams per cubic centimeter. Gas giants, on the other hand, have a density close to water at about one gram per cubic centimeter.

“Studying the radial velocity of the planet candidates Kepler discovers is a key endeavor in understanding our place in the cosmos. It will help answer one of humanity ’biggest questions, “Are we alone?” Armandroff said.

Marcy and his colleagues plan to start studying Kepler’s candidate Earths with Keck I and HIRES during the last three night of July 2009.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. The twin ten-meter telescopes were made possible by grants totaling $138 million from the W. M. Keck Foundation; the Keck I telescope began science observations in 1993, Keck II began in 1996.

Kepler is a NASA Discovery mission. NASA Ames Research Center, Moffett Field, Calif., is the home organization of the science principal investigator, and is responsible for the ground system development, mission operations and science data analysis. Jet Propulsion Laboratory, Pasadena, Calif., manages the Kepler mission development. Ball Aerospace & Technologies Corp. of Boulder, Colo., is responsible for developing the Kepler flight system and supporting mission operations. For more information about the Kepler mission, visit: http://www.nasa.gov/kepler.

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Maunakea Lecture Series Celebrates the International Year of Astronomy 2009

Hawai‘i Island, HI –  The public is invited to attend The Maunakea 2009 Lecture Series, free monthly lectures throughout 2009 hosted by ‘Imiloa Astronomy Center and W. M. Keck Observatory to introduce Hawai’i astronomy and the latest research being done by the thirteen observatories located on the summit of Maunakea.  The Maunakea 2009 Lecture Series is the first of many activities planned locally to commemorate the International Year of Astronomy (IYA 2009), a global celebration of astronomy and its contributions to society and culture, with events happening worldwide in 135 countries.

The opening speaker in the 2009 Series is Chad Kalepa Baybayan, ‘Imiloa Astronomy Center’s Navigator-in-Residence, whose presentation will be Thursday, January 15 at the W. M. Keck Observatory’s Hualalai Learning Theater in Waimea and Saturday, January 17 at ‘Imiloa Astronomy Center’s planetarium in Hilo.  Both programs begin at 7 pm and space is limited to first-come, first served. 

Baybayan’s talk titled, “Traditional Hawaiian Navigation and Sky Lore,” will discuss how the earliest astronomers, the Hawaiians, used their powers of observation and knowing the movement of stars, as well as understanding of ocean and environmental conditions, for navigation and wayfinding.

Baybayan holds a masters degree in Education, is a fluent speaker of the Hawaiian language, and has served as captain and navigator aboard the Hawaiian deep-sea voyaging canoes Hōkūle‘a, Hawai’iloa, and Hōkūalaka’i. He has been an active participant in the Polynesian voyaging movement since 1975 and has sailed on all major voyages of the Hōkūle’a throughout Polynesia, Micronesia, the west coast of North America, and Japan. Currently he serves as the Navigator-in-Residence at the ‘Imiloa Astronomy Center of Hawai’i. He also serves as the resident captain and navigator aboard Hōkūalaka’i, the newest of a fleet of voyaging canoes that are symbolic of the growing interest among local Hawaiian communities in the voyaging arts. He is currently working to establish Hōkūalaka’i as a cornerstone voyaging program located in Keaukaha, a Hawaiian homestead community, on the island of Hawai‘i.

Following Baybayan’s talk, there will be presentations over the next eleven months by the directors of the Maunakea observatories who will share the latest scientific discoveries and technologies from their research facilities.  Over the last 400 years, telescopes and techniques have evolved to include instruments that “see” the heavens in many ways.  The telescopes on Maunakea each have unique capabilities, and many are world leaders in this legacy of exploration.

The programs in Hilo will take place in ‘Imiloa Astronomy Center’s 120-seat planetarium on the third Saturday of each month during 2009.  This special year-long program replaces the Center’s monthly “Maunakea Skies” planetarium talks, which will resume in 2010.  In addition to hearing the lecture, guests may also choose to dine before hand at ‘Imiloa’s Sky Garden Restaurant which will be open for dinner service from 5 pm to 8 pm.  For dinner reservations, call the restaurant directly at (808) 935-8888.

Opened in 2006, ‘Imiloa Astronomy Center celebrates both Hawaiian culture and Maunakea astronomy.  Through its exhibits and program, ‘Imiloa strives to share inspiring examples of science and culture together advancing knowledge, understanding and opportunity.  The Center is located at 600 ‘Imiloa Place in Hilo, off Komohana and Nowelo Streets at the UH-Hilo Science and Technology Park. For more information, go to http://www.imiloahawaii.org  or call (808) 969-9700 for recorded information, or (808) 969-9703.

The programs in Waimea take place at the W. M. Keck Observatory headquarters in the Hualalai Learning Theater at 65-1120 Mamalahoa Highway.  Keck Observatory operates twin 10-meter optical/infrared telescopes made possible by grants totaling more than $138 million from the W. M. Keck Foundation.  Keck I telescope began science observations in 1993, Keck II began in 1996.  The vision of the Keck Observatory is a world in which all humankind is inspired and united by the pursuit of knowledge of the infinite variety and richness of the Universe.  The W.M. Keck Observatory headquarters operates a small visitor/information center open to the public from 9:00 a.m. to 4:30 p.m. Monday through Friday.  For more information, visit http://www.keckobservatory.org  or call (808) 885-7887.

Discovery of Methane Reveals Mars Is Not a Dead Planet

WASHINGTON—A team of NASA and university scientists has achieved the first definitive detection of methane in the atmosphere of Mars. This discovery indicates the planet is either biologically or geologically active.

The team found methane in the Martian atmosphere by carefully observing the planet throughout several Mars years with NASA’s Infrared Telescope Facility and the W.M. Keck telescope, both at Mauna Kea, Hawaii. The team used spectrometers on the telescopes to spread the light into its component colors, as a prism separates white light into a rainbow. The team detected three spectral features called absorption lines that together are a definitive signature of methane.

“Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas,” said Michael Mumma of NASA’s Goddard Space Flight Center in Greenbelt, Md. “At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif.” Mumma is lead author of a paper describing this research that will appear in Science Express on Thursday.

Methane, four atoms of hydrogen bound to a carbon atom, is the main component of natural gas on Earth. Astrobiologists are interested in these data because organisms release much of Earth’s methane as they digest nutrients. However, other purely geological processes, like oxidation of iron, also release methane.

“Right now, we do not have enough information to tell whether biology or geology—or both—is producing the methane on Mars,” Mumma said. “But it does tell us the planet is still alive, at least in a geologic sense. It is as if Mars is challenging us, saying, ‘hey, find out what this means.’ ”

If microscopic Martian life is producing the methane, it likely resides far below the surface where it is warm enough for liquid water to exist. Liquid water is necessary for all known forms of life, as are energy sources and a supply of carbon.

“On Earth, microorganisms thrive about 1.2 to 1.9 miles beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen and oxygen,” Mumma said. “The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon. Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons.”

It is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide and the planet’s internal heat. Although there is no evidence of active volcanism on Mars today, ancient methane trapped in ice cages called clathrates might be released now.

“We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane,” said co-author Geronimo Villanueva of the Catholic University of America in Washington. “The plumes were emitted during the warmer seasons, spring and summer, perhaps because ice blocking cracks and fissures vaporized, allowing methane to seep into the Martian air.”

According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. Plumes appeared over the Martian northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano about 745 miles across.

One method to test whether life produced this methane is by measuring isotope ratios. Isotopes of an element have slightly different chemical properties, and life prefers to use the lighter isotopes. A chemical called deuterium is a heavier version of hydrogen. Methane and water released on Mars should show distinctive ratios for isotopes of hydrogen and carbon if life was responsible for methane production. It will take future missions, like NASA’s Mars Science Laboratory, to discover the origin of the Martian methane.

The research was funded by the Planetary Astronomy Program at NASA Headquarters in Washington and the Astrobiology Institute at NASA’s Ames Research Center in Moffett Field, Calif. The University of Hawaii manages NASA’s Infrared Telescope Facility.

For images related to this finding, visit:

http://www.nasa.gov/mars 

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Astronomers use gamma-ray burst to probe star formation in the early universe

LONG BEACH, CA (January 6th, 2009) The brilliant afterglow of a powerful gamma-ray burst (GRB) has enabled astronomers to probe the star-forming environment of a distant galaxy, resulting in the first detection of molecular gas in a GRB host galaxy. By analyzing the spectrum of light emitted in the GRB afterglow, the researchers are gleaning insights into an active stellar nursery in a galaxy so far away it appears as it was 10 billion years ago.

“This observation required a rare and exceptionally bright event to allow us to probe the fragile environment where stars were forming just 3 billion years after the Big Bang. After correcting for the extreme dust extinction, this is intrinsically the second brightest GRB afterglow to date; it would have been easily observed with amateur telescopes, if not for the dust in the way,” said Jason X. Prochaska, professor of astronomy and astrophysics at the University of California, Santa Cruz.

Prochaska’s team will present its findings at the American Astronomical Society meeting this week in Long Beach, Calif. A paper describing the results has been accepted for publication in Astrophysical Journal Letters.

Stars form in vast clouds of molecular gas and dust, and astronomers have expected to find evidence of these molecular clouds in GRB host galaxies. Until now, however, efforts to detect molecular gas in GRB afterglow spectra had been unsuccessful. The new observations by Prochaska and his coauthors indicate that star formation in the early universe occurred in environments similar to star-forming regions in the Milky Way.

The study focused on a “long duration” gamma-ray burst known as GRB 080607. This type of burst is thought to occur when a massive star collapses to form a black hole. The initial burst of high-energy gamma rays was followed by a slowly fading afterglow of radiation over the entire spectrum of wavelengths.

“We suspect that previous events like 080607 were too faint to be observed on Earth,” said coauthor Yaron Sheffer of the University of Toledo. “Many so-called dark bursts, with no observable afterglow, probably mark the dusty, highly extinguished environments of young star-forming regions.”

NASA’s Swift satellite detected the gamma-ray burst and began x-ray observations, while alerting astronomers and triggering automatic observations by ground-based telescopes such as the Katzman Automatic Imaging Telescope at Lick Observatory. Team members Joshua Bloom, Daniel Perley, and Adam Miller of UC Berkeley happened to be using the Keck I Telescope at the W. M. Keck Observatory in Hawaii and began spectroscopic observations within 15 minutes using the Low Resolution Imaging Spectrograph (LRIS).

The resulting spectrum of the optical afterglow yielded information about the dust, gas, and metals in the interstellar medium through which the light passed on its way out of the host galaxy. In addition to the first clear detection of molecular gases (both carbon monoxide and hydrogen), the spectrum indicated a metal composition comparable to that of the Sun (to astronomers, “metals” are elements heavier than hydrogen and helium).

The spectrum also has many features researchers have never seen before, Prochaska said. In addition to hundreds of standard absorption lines corresponding to known transitions of various elements, the spectrum shows many absorption lines that researchers have yet to identify.

“This is easily the most fascinating spectrum that I’ve ever worked on,” Prochaska said. “Nearly half of the features remain a mystery, and it is possible that no one has ever detected them previously, either in controlled laboratory experiments or in spectra from our galaxy or other galaxies.”

There is also more hydrogen in this spectrum than along any path through the Milky Way, he added. “This remains a bit of a puzzle,” Prochaska said. “For now, we don’t know much about the galaxy that hosted the explosion, but the evidence suggests it has been prodigious in terms of star formation.”

The burst and its afterglow were observed in June, and the team did not manage to get images of the host galaxy before it moved to a position in the sky where it could not be observed. In January, the researchers will image the galaxy to connect their findings on the star-forming region with its global properties.

In addition to Prochaska, Sheffer, Perley, Miller, and Bloom, the coauthors include Laura Lopez of UC Santa Cruz; Miroslava Dessauges-Zavadsky of the Geneva Observatory, Switzerland; Hsiao-Wen Chen of the University of Chicago; and Alex Filippenko, Mo Ganeshalingam, Weidong Li, and Dan Starr of UC Berkeley.

This research was supported by the National Science Foundation, NASA, and the TABASGO Foundation.

ASTRONOMERS CAPTURE FIRST IMAGES OF NEWLY-DISCOVERED PLANETARY SYSTEM

Kamuela, HI (November 13th, 2008) Using high-contrast, near-infrared adaptive optics observations with the Keck and Gemini telescopes atop Mauna Kea, astronomers for the first time have taken snapshots of a multi-planet solar system, much like ours, orbiting another star.

The new solar system orbits the dusty young star named HR8799, which is 140 light years away and about 1.5 times the size of our sun. Three planets, roughly 10, 10 and 7 times the mass of Jupiter, orbit the star. The sizes of the planets decrease with distance from the parent star, much like the giant planets do in our system.

And there may be more planets out there that scientists just haven’t seen yet.
“Every extrasolar planet detected so far has been a wobble on a graph. These are the first pictures of an entire system,” said Bruce Macintosh, an astrophysicist from Lawrence Livermore National Laboratory and one of the key authors of a paper appearing in the Nov. 13 issue of Science Express. “We’ve been trying to image planets for eight years with no luck and now we have pictures of three planets at once.”

The team of researchers from Livermore, the NRC Herzberg Institute of Astrophysics in Canada, Lowell Observatory, UCLA, and several other institutions were able to see three orbiting planetary companions to HR 8799. The first author of the paper is Christian Marois, a former Livermore postdoctoral researcher who now works at NRC.

Astronomers have known for a decade through indirect techniques that the sun was not the only star with orbiting planets.

“But we finally have an actual image of an entire system,” Macintosh said. “This is a milestone in the search and characterization of planetary systems around stars.”

During the past 10 years, various planet detection techniques have been used to find more than 200 exoplanets. But these methods all have limitations. Most infer the existence of a planet through its influence on the star that it orbits, but don’t actually tell scientists anything about the planet other than its mass and orbit. Second, the techniques are all limited to small to moderate planet-star separation, usually less than about 5 AU. (Astronomical units; one AU is the average distance from the sun to Earth).

In the new findings, the planets are 24, 37 and 67 times the Earth-sun separation from the host star. The furthest planet in the new system orbits just inside a disk of dusty debris, similar to that produced by the comets of the Kuiper belt of our solar system (just beyond the orbit of Neptune at 30 times Earth-sun distance).

“HR 8799’s dust disk stands out as one of the most massive in orbit around any star within 300 light years of Earth,” said UCLA’S Ben Zuckerman.

In some ways, this planetary system seems to be a scaled-up version of our solar system orbiting a larger and brighter star.

The host star is a bright, blue A-type star, which has been mostly neglected in ground and space-based direct imaging survey since it offers a less favorable contrast between the bright star and faint planet. But they do have an advantage over our sun: early in their life, they can retain heavy disks of planet-making material and therefore form more massive planets at wider separations that are easier to detect. This star is also young - less than 100 million years old - which means its planets are still glowing with heat from their formation.

“Seeing these planets directly - separating their light from the star - lets us study them as individuals, and use spectroscopy to study their properties, like temperature or composition,” Macintosh said.

“Detailed comparison with theoretical model atmospheres confirms that all three planets possess complex atmospheres with dusty clouds partially trapping and re-radiating the escaping heat,” said Lowell Observatory astronomer Travis Barman.

The planets have been extensively studied using adaptive optics on the giant Keck and Gemini telescopes in Hawaii. Adaptive optics enables astronomers to minimize the blurring effects of the Earth’s atmosphere, producing images with unprecedented detail and resolution. LLNL helped build the original adaptive optics system for Keck, the world’s largest optical telescope. Marois developed an advanced computer processing technique that helps to extract the planets from the vastly brighter light of the star.

Keck Observatory Director Taft Armandroff is pleased with this new discovery enabled by adaptive optics. “In 1999, the Keck II telescope became the first large telescope worldwide to develop and install an adaptive optics system. The results have been dramatic. Keck’s adaptive optics systems routinely produce images with significantly greater clarity and detail than those resulting from Hubble Space Telescope. Keck is developing a next generation system that will produce images that are nearly perfectly corrected for atmospheric turbulence at infrared wavelengths, plus it will enable adaptive optics correction at optical wavelengths for the first time and increase the current very narrow fields of view that limit current adaptive optics systems,” Armandroff reported.

“I think there’s a very high probability that there are more planets in the system that we can’t detect yet,” Macintosh said. “One of the things that distinguishes this system from most of the extrasolar planets that are already known is that HR8799 has its giant planets in the outer parts - like our solar system does - and so has ‘room’ for smaller terrestrial planets - far beyond our current ability to see - in the inner parts.”

The W. M. Keck Observatory (http://www.keckobservatory.org) is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. The twin ten-meter telescopes were made possible by grants totaling $138 million from the W. M. Keck Foundation; the Keck I telescope began science observations in 1993, Keck II began in 1996.

Keck Telescope and Cosmic Lens Resolve Nature and Fate of Early Star-Forming

PASADENA, Calif. (October 15th, 2008) Astronomers at the California Institute of Technology (Caltech) and their colleagues have provided unique insight into the nature of a young star-forming galaxy as it appeared only two billion years after the Big Bang and determined how the galaxy may eventually evolve to become a system like our own Milky Way.

The team made their observations by coupling two techniques, gravitational lensing—which makes use of an effect first predicted by Albert Einstein in which the gravitational field of massive objects, such as foreground galaxies, bends light rays from objects located a distance behind, thus magnifying the appearance of distant sources—and laser-assisted guide star (LGS) adaptive optics (AO) on the 10-meter Keck Telescope in Hawaii. Adaptive optics corrects the blurring effects of Earth’s atmosphere by real-time monitoring of the signal from a natural guide star or an artificial guide star. Gravitational lensing enlarged the distant galaxy in angular size by a factor of about 8 in each direction. Together with the enhanced resolution using adaptive optics, this allowed the team to determine the internal velocity structure of the remote galaxy, located 11 billion light-years from Earth, and hence its likely future evolution.

The researchers found that the distant galaxy, which is typical in many respects to others at that epoch, shows clear signs of orderly rotation. The finding, in association with observations conducted at millimeter wavelengths, which are sensitive to cold molecular gas (an indicator of galactic rotation), suggests that the source is in the early stages of assembling a spiral disk with a central nucleus similar to those seen in spiral galaxies at the present day.

Using the Hubble Space Telescope, the team located a distinctive galaxy dubbed the “Cosmic Eye” because its form is distorted into a ring-shaped structure by the gravitational field of a foreground galaxy.

“Gravity has effectively provided us with an additional zoom lens, enabling us to study this distant galaxy on scales approaching only a few hundred light-years. This is 10 times finer sampling than hitherto possible,” explains postdoctoral research scholar Dan Stark of Caltech, the leader of the study. “As a result, we can see, for the first time, that a typical-sized young galaxy is spinning and slowly evolving into a spiral galaxy much like our own Milky Way,” he says.

The research, described in the October 9 issue of the journal Nature, provides a demonstration of the likely power of the future Thirty Meter Telescope (TMT), the first of a new generation of large telescopes designed to exploit AO.

When completed in the latter half of the next decade, TMT’s large aperture and improved optics will produce images with an angular resolution three times better than the 10-meter Keck and 12 times better than the Hubble Space Telescope, at similar wavelengths. Because of the significant improvement in angular resolution provided by AO, the TMT will be able to study the internal properties of small distant galaxies, seen as they were when the universe was young.

Likewise, the Atacama Large Millimeter Array (ALMA), a large interferometer being completed in Chile, will provide a major step forward in mapping the extremely faint emission from cold hydrogen gas—the principal component of young, distant galaxies and a clear marker of cold molecular gas—compared to the coarser capabilities of present facilities. In their recent research, the Caltech-led team has provided a glimpse of what can be done with the superior performance expected of TMT and ALMA.

The key spectroscopic observations were made with the OSIRIS instrument, developed specifically for the Keck AO system by astrophysicist James Larkin and collaborators at the University of California, Los Angeles. Stark and his coworkers used the OSIRIS instrument to map the velocity across the source in fine detail, allowing them to demonstrate that it has a primitive rotating disk.

To aid in their analysis, the researchers combined data from the Keck Observatory with data taken at millimeter wavelengths by the Plateau de Bure Interferometer (PdBI), located in the French Alps. This PdBI instrument is sensitive to the distribution of cold gas that has yet to collapse to form stars. These observations give a hint of what will soon be routine with the ALMA interferometer.

“Remarkably, the cold gas traced by our millimeter observations shares the rotation shown by the young stars seen in the Keck observations. The distribution of gas seen with our amazing resolution indicates we are witnessing the gradual buildup of a spiral disk with a central nuclear component,” explains coinvestigator Mark Swinbank of Durham University, who was involved in both the Keck and PdBI observations.

This work demonstrates how important angular resolution has become in ensuring progress in extragalactic astronomy. This will be the key gain of both the TMT and ALMA facilities.

“For decades, astronomers were content to build bigger telescopes, arguing that light-gathering power was the primary measure of a telescope’s ability,” explains Richard S. Ellis, Steele Family Professor of Astronomy at Caltech, a coauthor on the Nature study, and a member of the TMT board of directors. “However, adaptive optics and interferometry are now providing ground-based astronomers with the additional gain of angular resolution. The combination of a large aperture and exquisite resolution is very effective for studying the internal properties of distant and faint sources seen as they were when the universe was young. This is the exciting future we can expect with TMT and ALMA, and, thanks to the magnification of a gravitational lens, we have an early demonstration here in this study,” he says.

Coauthors on the paper, “The formation and assembly of a typical star-forming galaxies at redshift z~3,” are Simon Dye of Cardiff University in Cardiff, Wales; Ian R. Smail of Durham University in Durham, England; and Johan Richard of Caltech.

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea. The observatory, made possible by grants from the W. M. Keck Foundation totaling over $138 million, is managed as a nonprofit corporation whose board of directors includes representatives from Caltech and the University of California.

The Thirty Meter Telescope is currently in a detailed design and development phase and represents a collaboration between Caltech, the University of California, and the Association for Canadian Universities Research in Astronomy. It has received generous support from the Gordon and Betty Moore Foundation.

Further information on the Thirty Meter Telescope is available at http://www.tmt.org. and: http://www.tmt.org/news/cosmic-lens.htm

Information on the Atacama Large Millimeter Array is available at http://www.alma.nrao.edu.

Further information on the Keck telescopes, their adaptive optics systems, and the OSIRIS instrument are available at: https://www.keckobservatory.org/.

KECK OBSERVATORY OPEN HOUSE SUNDAY, OCTOBER 12, 2008: WELCOME TO THE EDGE OF DISCOVERY

(September 4th, 2008) W. M. Keck Observatorys 2008 Open House will feature “hands-on activities” and displays presenting the science, technology and excitement of astronomy.

MOST BLACK HOLES MIGHT COME IN ONLY SMALL AND LARGE

(August 20th, 2008) Black holes are sometimes huge cosmic beasts, billions of times the mass of our sun, and sometimes petite with just a few times the sun’s mass. But do black holes also come in size medium? Research combining data from the European Space Agency’s XMM-Newton space telescope and the W. M. Keck Observatory suggests that, for the most part, the answer is no.

Astronomers have long suspected that the most likely place to find a medium-mass black hole would be at the core of a miniature galaxy-like object called a globular cluster. Yet, nobody has been able to find one conclusively.

Now, a team of astronomers has thoroughly examined a globular cluster called RZ2109 and determined that it cannot possess a medium black hole. The findings suggest that the elusive objects do not lurk in globular clusters, and perhaps are very rare.

“Some theories say that small black holes in globular clusters should sink down to the center and form a medium-sized one, but our discovery suggests this isn’t true,” said Daniel Stern of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. Stern is second author of a study detailing the findings in the Aug. 20 issue of Astrophysical Journal. The lead author is Stephen Zepf of Michigan State University, East Lansing.

Black holes are incredibly dense points of matter, whose gravity prevents even light from escaping. The least massive black holes known are about 10 times the mass of the sun and form when massive stars blow up in supernova explosions. The heftiest black holes are up to billions of times the mass of the sun and lie deep in the bellies of almost all galaxies.

That leaves black holes of intermediate mass, which were thought to be buried at the cores of globular clusters. Globular clusters are dense collections of millions of stars, which reside within galaxies containing hundreds of billions of stars. Theorists argue that a globular cluster should have a scaled down version of a galactic black hole. Such objects would be about 1,000 to 10,000 times the mass of the sun, or medium in size on the universal scale of black holes.

In a previous study, Zepf and his colleagues looked for evidence of a black hole in RZ2109, located 50 million light-years away in a nearby galaxy. Using ESA’s XMM-Newton telescope (which derives its name from X-ray Multi-Mirror design), they discovered the telltale X-ray signature of an active, or “feeding” black hole. But, at that point, they still didn’t know its size.

Zepf and Stern then teamed up with others to obtain a chemical fingerprint, called a spectrum, of the globular cluster, using the W.M. Keck Observatory on Mauna Kea in Hawaii. The spectrum revealed that the black hole is petite, with roughly 10 times the mass of our sun.

According to theory, a cluster with a small black hole cannot have a medium one too. Medium black holes would be quite hefty with a lot of gravity, so if one did exist in a globular cluster, scientists argue that it would quickly drag any small black holes into its grasp.

“If a medium black hole existed in a cluster, it would either swallow little black holes or kick them out of the cluster,” said Stern. In other words, the small black hole in RZ2109 rules out the possibility of a medium one.

How did the scientists figure out that the globular cluster’s black hole was small in the first place? Using modeling techniques, Zepf and his colleagues concluded that the spectrum taken by Keck reveals high-velocity flows of matter, or “winds,” firing out of the black hole. Only a small black hole could spit out these observed high winds.

Zepf explains, “We knew from X-ray data that this black hole was actively swallowing up, or accreting, material. If an intermediate-sized black hole were accreting this material, it wouldn’t be too big of a deal for it. But if a small black hole were accreting this material, it would be a lot for it to take and therefore some material would be ejected in the form of high winds. Thus, the high winds were our smoking gun showing that this black hole is small.”

Is this the end of the story for medium black holes? Zepf said that it is possible such objects are hiding in the outskirts of galaxies like our Milky Way, either in surrounding so-called dwarf galaxies or in the remnants of dwarf galaxies being swallowed by a bigger galaxy. If so, the black holes would be faint and difficult to find.

Other authors of this paper include: Thomas Maccarone of the University of Southampton, England; Arunav Kundu of Michigan State University; Marc Kamionkowski of the California Institute of Technology, Pasadena; Katherine Rhode and John Salzer of the Indiana University, Bloomington; and Robin Ciardullo and Caryl Gronwall of Penn State University, University Park, Pa. Salzer is also with the Wesleyan University, Middleton, Conn.

For more information, visit:
W. M. Keck Observatory
European Space Agency XMM Newton telescope
Jet Propulsion LaboratoryJet Propulsion Laboratory

RARE STAR MAKING MACHINE FOUND IN EARLY UNIVERSE

(July 11th, 2008) Astronomers have uncovered an extreme stellar machine of a galaxy in the very remote universe, pumping out stars at a surprising rate of up to 4,000 per year. In comparison, our own Milky Way galaxy turns out an average of just 10 stars per year. The discovery was made possible by combining data from several telescopes atop Mauna Kea and NASA’s Hubble and Spitzer Space Telescopes. The Keck II telescope together with the DEep Imaging Multi-Object Spectrograph (DEIMOS) were used to discover the galaxy lies in the distant universe. The extreme distance of 12.3 billion light years places it in the universe’s infancy.

“This galaxy is undergoing a major baby boom, producing most of its stars all at once,” said Peter Capak of NASA’s Spitzer Science Center at the California Institute of Technology, Pasadena. “If our human population was produced in a similar boom, then almost all of the people alive today would be the same age.” Capak is lead author of a new report detailing the discovery in the July 10th issue of Astrophysical Journal Letters.

The results go against the most common theory of galaxy formation. According to the theory, called the Hierarchical Model, galaxies slowly bulk up their stars over time by absorbing tiny pieces of galaxies—and not in one big burst as observed in the newfound “Baby Boom” galaxy.

The Baby Boom galaxy, which belongs to a class of galaxies called starbursts, is the new record holder for the brightest starburst galaxy in the very distant universe, with brightness being a measure of its extreme star-formation rate. It was discovered and characterized using a suite of telescopes operating at different wavelengths. NASA’s Hubble Space Telescope and Japan’s Subaru Telescope, atop Mauna Kea in Hawaii, first spotted the galaxy in visible-light images, where it appeared as an inconspicuous smudge due to is great distance.

It wasn’t until Spitzer and the James Clerk Maxwell Telescope, also on Mauna Kea in Hawaii, observed the galaxy at infrared and submillimeter wavelengths, respectively, that the galaxy stood out as the brightest of the bunch. This is because it has a huge number of youthful stars. When stars are born, they shine with a lot of ultraviolet light and produce a lot of dust. The dust absorbs the ultraviolet light but, like a car sitting in the sun, it warms up and re-emits light at infrared and submillimeter wavelengths, making the galaxy unusually bright to Spitzer and the James Clerk Maxwell Telescope.

To learn more about this galaxy’s unique youthful glow, Capak and his team followed up with a number of telescopes. They used optical measurements from Keck to determine the exact distance to the galaxy—a whopping12.3 billion light-years. That’s looking back to a time when the universe was 1.3 billion years old (the universe is approximately 13.7 billion years old today).

“If the universe was a human reaching retirement age, it would have been about 6 years old at the time we are seeing this galaxy,” said Capak.

The astronomers made measurements at radio wavelengths with the National Science Foundation’s Very Large Array in New Mexico. Together with Spitzer and James Clerk Maxwell data, these observations allowed the astronomers to calculate a star-forming rate of about 1,000 to 4,000 stars per year. At that rate, the galaxy needs only 50 million years, not very long on cosmic timescales, to grow into a galaxy equivalent to the most massive ones we see today.

While galaxies in our nearby universe can produce stars at similarly high rates, the farthest one known before now was about 11.7 billion light-years away, or a time when the universe was 1.9 billion years old.

“Before now, we had only seen galaxies form stars like this in the teenaged universe, but this galaxy is forming when the universe was only a child,” said Capak. “The question now is whether the majority of the very most massive galaxies form very early in the universe like the Baby Boom galaxy, or whether this is an exceptional case. Answering this question will help us determine to what degree the Hierarchical Model of galaxy formation still holds true.”

“The incredible star-formation activity we have observed suggests that we may be witnessing, for the first time, the formation of one of the most massive elliptical galaxies in the universe,” said Nick Scoville, the principal investigator of the Cosmic Evolution Survey, also known as Cosmos, and a co-author of the study. The Cosmos program is an extensive survey of a large patch of distant galaxies across the full spectrum of light.

“The immediate identification of this galaxy with its extraordinary properties would not have been possible without the full range of observations in this survey,” said Scoville.

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea. Made possible by grants from the W. M. Keck Foundation totaling over $138 million, the Observatory is managed as a non-profit corporation whose board of directors includes representatives from the California Institute of Technology and the University of California. For more information, visit http://www.keckobservatory.org

ASTRONOMERS WEIGH THE COLDEST BROWN DWARFS WITH ASTRONOMY’S SHARPEST EYES

Honolulu (June 2nd, 2008) Astronomers have used ultrasharp images obtained with the Keck Telescope and Hubble Space Telescope to determine for the first time the masses of the coldest class of “failed stars,” a.k.a. brown dwarfs. With masses as light as 3 percent the mass of the sun, these are the lowest mass free-floating objects ever weighed outside the solar system. The observations are a major step in testing the theoretical predictions of objects that cannot generate their own internal energy, both brown dwarfs and gas-giant planets. The new findings, which are being presented in a press conference today at the American Astronomical Society meeting in St. Louis, show that the predictions may have some problems.

“Mass is the fundamental parameter that governs the life-history of a free-floating object, and thus after many years of patient measurements, we are delighted to report the first masses of the very faintest, coldest brown dwarfs,” said Dr. Michael Liu of the Institute for Astronomy at the University of Hawaii (IfA/UH). “After weighing these tiny, dim, cold objects, we have confirmed that the theoretical predictions are mostly correct, but not entirely so.” The team announcing the results is composed of Dr. Liu, Mr. Trent J. Dupuy (IfA/UH), and Dr. Michael J. Ireland (University of Sydney).

Brown dwarfs are a class of objects that represent the missing link between the lowest-mass stars and the gas-giant planets, such as Jupiter and Saturn. Brown dwarfs are the faintest and coolest objects that can be directly observed outside the solar system. They emit as little as about 1/300,000 the energy of the sun and have surface temperatures comparable to the inside of a pizza oven (800° F), more than 9,000° F cooler than the surface of the sun.

“Astronomers have measured the energy output and temperatures for a myriad of brown dwarfs. However, the most important property of all is the hardest one to measure—the mass,” said Dr. Ireland.

To determine the masses, the team has spent the last several years studying brown dwarfs that occur in binaries, that is two brown dwarfs that are mutually bound together by gravity and orbit each other, in a fashion similar to how Earth orbits the sun. As first shown by Johannes Kepler in the 17th century, the total mass of any binary system can be determined by precisely measuring the orbit’s size and how long it takes for the two objects to complete one orbital cycle.

“These are very challenging measurements, because brown dwarf binaries have tiny separations on the sky and orbit each other very slowly. We needed to obtain the sharpest measurements that are possible with current telescopes to precisely monitor their motion,” said Mr. Dupuy.

The astronomers obtained images using the 10-meter (400-inch) Keck II Telescope on Mauna Kea, Hawaii. Keck II is equipped with a powerful adaptive optics system that corrects for the blurring of astronomical images caused by turbulence in Earth’s atmosphere. The Keck system can also employ a low-power laser to create an “artificial” star to enable such correction for almost anywhere in the sky.

The resulting images have an angular resolution as good as 1/20 of an arc second, about 1/40,000 the diameter of the full moon. A person with vision as sharp as the Keck adaptive optics system would be able to read a magazine that was about a mile away. In fact, the positional accuracy achieved with such sharp images is equivalent to hitting a bull’s-eye on a dartboard that is 8,000 miles away.

By regularly monitoring binaries with Keck adaptive optics and analyzing previous data obtained by the Hubble Space Telescope, the team was able to precisely measure the size and duration of the binaries’ orbits, and thereby determine the masses.

The team measured the masses of two brown dwarf binaries. One, known as 2MASS 1534-2952AB, is composed of two “methane” brown dwarfs, the coolest type of brown dwarf, which is characterized by the presence of methane gas in their atmospheres. This is the first mass measurement for this type of brown dwarf. The team found that the total mass of 2MASS 1534-2952AB is only 6 percent of the sun’s mass, and each brown dwarf in it has a mass of about 3 percent of the sun’s (about 30 times the mass of Jupiter). The other binary system, HD 130948BC, is a pair of slightly warmer “dusty” brown dwarfs with a total mass of only 11 percent of the sun’s mass and individual masses of about 5.5 percent of the sun’s.

Theoretical models predict the masses of brown dwarfs based on their energy output and temperature. But when the team compared their mass measurements to the theoretical predictions, they did not agree. For example, the surface temperature of 2MASS 1534-2952AB was much cooler than expected given its current level of energy output, while HD 130948BC was much warmer.

“While there is general agreement between our data and the predictions, something is not quite right with the theoretical studies of brown dwarfs, either in determining their temperatures or in predicting their energy output. Or perhaps both,” said Dr. Liu. “These findings will be a challenge for the theorists, and we are inspired to measure the masses of more brown dwarfs in the coming years to better understand the problem.”

The two binaries, located in the constellations of Libra (the Scales) and Bootes (the Herdsman), are about 45-60 light-years from Earth. The two components of each binary have a typical separation of about 2 astronomical units (AU), where 1 AU is the distance from Earth to the sun (93 million miles). This is somewhat larger than the 1.5 AU distance between Mars and the sun. Their orbital periods are about 10-15 years, compared with 2 years for Mars around the sun.

The team’s results are described in two upcoming papers submitted to the Astrophysical Journal. This research has been supported by the National Science Foundation and the Alfred P. Sloan Foundation.

First discovered in 1995, brown dwarfs represent a class of objects with masses less than 7 percent the mass of the sun (about 70 times Jupiter’s mass). While ordinary stars become hot and dense enough in their interiors to generate their own energy via nuclear fusion, brown dwarfs have insufficient mass to do this, so instead they steadily fade and cool over their lifetime. In many ways, brown dwarfs are very similar to gas-giant planets like Jupiter and Saturn, since both types of objects are unable to steadily generate their own energy and have very low surface temperatures.

FIGURE CAPTIONS

Figure 1. Infrared image of the very low-temperature binary 2MASS 1534-2952AB, composed of two methane brown dwarfs. This was obtained with the laser guide star adaptive optics system on the Keck II Telescope, located on Mauna Kea, Hawaii. The image is 1.5 arc seconds across (about 1/1,000 of the size of the moon), and the binary’s separation is about 0.2 arc seconds. Each component of the binary has a mass of about 3 percent the mass of the sun and emits about 1/100,000 the energy of the sun. These are the coolest free-floating objects ever directly weighed outside the solar system. Credit: Dr. Michael Liu (Institute for Astronomy, University of Hawaii).

Figure 2. Infrared image of the dusty brown dwarf binary HD 130948BC. The binary is seen in the upper left and has a total mass about 11 percent the mass of the sun. The binary is in orbit around a young sun-like star, seen to the lower right. This image was obtained with the adaptive optics system on the Keck II Telescope, located on Mauna Kea, Hawaii. The image is 3.75 arc seconds on a side (about 1/500 the size of the moon), and the binary’s separation is about 0.1 arc seconds. Credit: Mr. Trent Dupuy and Dr. Michael Liu (Institute for Astronomy, University of Hawaii).

Founded in 1967, the Institute for Astronomy at the University of Hawaii at Manoa conducts research into galaxies, cosmology, stars, planets, and the sun. Its faculty and staff are also involved in astronomy education, deep space missions, and in the development and management of the observatories on Haleakala and Mauna Kea.

Established in 1907 and fully accredited by the Western Association of Schools and Colleges, the University of Hawaii is the state’s sole public system of higher education. The UH System provides an array of undergraduate, graduate, and professional degrees and community programs on 10 campuses and through educational, training, and research centers across the state. UH enrolls more than 50,000 students from Hawaii, the U.S. mainland, and around the world.

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea on the island of Hawaii and is managed by the California Association for Research in Astronomy, a non-profit corporation whose board of directors includes representatives from Caltech and the University of California. For more information, please visit: http://www.keckobservatory.org.

The Hubble Space Telescope is operated by the Space Telescope Science Institute with funding from NASA.

KECK, HUBBLE IMAGES SHOW CONTINUED TURBULENCE IN JUPITER’S ATMOSPHERE

Berkeley (May 22nd, 2008) Increased turbulence and storms first observed on Jupiter more than two years ago are still raging, according to astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii, who snapped high-resolution pictures of the planet earlier this month.

Captured with NASA’s Hubble Space Telescope (HST) and the 10-meter Keck II telescope, this so-called “major upheaval” on Jupiter involves stunning changes in the planet’s atmosphere, said lead astronomer Imke de Pater, professor of astronomy at UC Berkeley.

The images are available on NASA’s Web site, NASA’s HubbleSite NewsCenter

The upheaval was heralded in December 2005 by a color change from white to red of a large oval near the Great Red Spot, earning it the moniker Red Spot Jr. This oval, formally known as Oval BA, formed six years earlier through a merger of three large white ovals just south of the Great Red Spot – storms that formed in the early 1930s and were prominent in the Voyager era.

The new images, the first since Jupiter emerged from its passage behind the Sun, may show that Jupiter indeed is undergoing a major climate change, as predicted four years ago.

“One of the most notable changes we observe in both the Hubble and Keck images is the change from a rather bland, quiescent band surrounding the Great Red Spot just over a year ago to one that is incredibly turbulent at both sides of the spot,” de Pater said. “During all previous HST observations and spacecraft encounters, starting with Voyager in 1979, such turbulence was seen only on the west or left side of the spot.”

The Great Red Spot is a persistent, high-pressure storm on Jupiter whose cloud head sticks some 8 kilometers (5 miles) above the surrounding cloud deck. Why the spots are red is a subject of great debate.

Moreover, the color of several bands on the planet has been changing since the upheaval began, said Christopher Go, an amateur astronomer in Cebu, the Philippines, who joined de Pater’s team two years ago. Go alerted the astronomical community in early 2006 about the color change of Red Spot Jr.

“Lately, the red color of the Oval BA has faded a little bit, while the Great Red Spot may have turned dark red,” Go said.

The UC Berkeley team will work with the amateur astronomy community to investigate the possible origin of this turbulence, which is not understood.

The Great Red Spot and Red Spot Jr. are squeezed between bands called shear flows, where the flow above each storm is moving westward and the flow below is moving eastward. Since the shear flow in each band is slightly different, and the storms are different sizes, Red Spot Jr. drifts slowly eastward toward the Great Red Spot while the Great Red Spot drifts slightly westward toward Red Spot Jr. In late June, this storm will pass the Great Red Spot, as it does every two years.

Interestingly, a third red spot has appeared to the west of the Great Red Spot in the same latitude band.

“Although much smaller in extent, the color is striking,” said UC Berkeley team member Michael Wong. ““Like the other two large red storm systems, this newest red spot is bright in near-infrared wavelengths and dark in the ultraviolet. If this spot and the Great Red Spot continue on their courses, they will encounter each other in August, and the small oval will either be absorbed or repelled from the Great Red Spot.”

According to Philip S. Marcus, a professor of fluid dynamics at UC Berkeley, analysis of the Hubble and Keck images may support his 2004 conjecture that Jupiter is in the midst of global climate change that will alter temperatures by as much as 10 degrees Celsius, getting warmer near the equator and cooler near the south pole. He predicted that large changes would start in the southern hemisphere around 2006, causing the jet streams to become unstable and spawn new vortices.

“The appearance of the planet’s cloud system from just north of the equator down to 34 degrees south latitude keeps surprising us with changes and, in particular, with new cloud features that haven’t been previously observed,” Marcus said. “Whether or not Jupiter’s climate has changed due to a predicted warming, the cloud activity over the last two and a half years shows dramatically that something unusual has happened.”

“A major goal in taking the Hubble images is to look for changes in the zonal wind profile since the Cassini encounter in 2000,” added team member Xylar Asay-Davis. “If we do find major changes, these could provide important supporting evidence for climate change on Jupiter.”

The red coloration in the ovals may be generated as their swirling hazes rise to heights like the clouds of the Great Red Spot. Detailed analysis of the Hubble’s visible light data and the Keck images at near-infrared wavelengths will reveal the relative altitudes of the cloud tops of the three red ovals, de Pater said. Since all three oval storms are bright at near-infrared wavelengths where methane gas is absorbing, the data already show that all three systems rise up well above the surrounding cloud deck.

The Hubble telescope imaged the entire planet on May 9 and 10 using the Wide-Field Planetary Camera 2, while Keck II focused on the area around the Great Red Spot on May 11 using adaptive optics to sharpen the image.

Dr. Al Conrad, a support astronomer at the Keck Observatory, noted that the team used adaptive optics (AO) to obtain a spatial resolution comparable to that obtained at visible wavelengths with the Hubble telescope. Adaptive optics can take the twinkle out of an object caused by turbulence in the atmosphere, but to do this well, the target must be near another bright object that can serve as a reference. For some of the images, Jupiter’s moon Europa was used as the reference “star.” But until Europa was visible off the limb of Jupiter, a laser guide star was created near Jupiter to serve this purpose.

“This was our second attempt using the laser to obtain AO-corrected images of Jupiter’s surface,” Conrad said. “Based on our past experience, we placed the laser beacon slightly farther from Jupiter’s bright glow. With this adjustment in place, AO revealed much finer detail on the surface than we saw during our previous observation. By using the laser whenever there is no moon available as an AO reference, we will now have many more opportunities to observe Jupiter with Keck.”

In addition to images at 1.2-1.65 microns, where Jupiter’s reflected infrared light is measured, the team also obtained a close-up of the three spots at the somewhat longer infrared wavelength of 5 microns that samples thermal radiation from deeper in the atmosphere. All three spots appear dark on the 5-micron image because the clouds obscure heat emanating from lower elevations.

‘‘This image is spectacular,’’ says de Pater. “There is an amazing amount of fine structure and numerous small ovals south of the spots. This image reveals details in the cloud opacity not seen at the other wavelengths.”

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea on the island of Hawaii and is managed by the California Association for Research in Astronomy, a non-profit corporation whose board of directors includes representatives from Caltech, the University of California and NASA. For more information, please visit: http://www.keckobservatory.org.

The Hubble Space Telescope is operated by the Space Telescope Science Institute with funding from NASA.

The Hubble team consisted of de Pater, Marcus, Wong and Asay-Davis of UC Berkeley and Go of the Philippines. The Keck team members were de Pater, Wong and Conor Laver of UC Berkeley and Conrad of the Keck Observatory. The contributions by the amateur network http://jupos.privat.t-online.de/ was invaluable for this research.

NOTE: Imke de Pater; Michael Wong, Phil Marcus and Al Conrad can be reached at .(JavaScript must be enabled to view this email address), .(JavaScript must be enabled to view this email address), .(JavaScript must be enabled to view this email address) and .(JavaScript must be enabled to view this email address), respectively.

For more information on Jupiter’s recent turbulence, link to Christopher Go’s Web site: http://jupiter.cstoneind.com.

COMPACT GALAXIES IN EARLY UNIVERSE PACK A BIG PUNCH

Baltimore, Md. (April 29th, 2008) Imagine receiving an announcement touting the birth of a baby 20 inches long and weighing 180 pounds. After reading this puzzling message, you would immediately think the baby’s weight was a misprint.

Astronomers using NASA’s Hubble Space Telescope and the W.M. Keck Observatory on Mauna Kea, Hawaii, received a similar perplexing announcement when they found nine young, compact galaxies, each weighing in at 200 billion times the mass of the Sun. The galaxies, each only 5,000 light-years across, existed 11 billion years ago, when the universe was less than 3 billion years old. They are a fraction of the size of today’s grownup galaxies but contain approximately the same number of stars. Each galaxy could fit inside the central hub of our Milky Way Galaxy.

“Seeing the compact sizes of these galaxies is a puzzle,” said Pieter G. van Dokkum of Yale University in New Haven, Conn., who led the study. “No massive galaxy at this distance has ever been observed to be so compact. It is not yet clear how they would build themselves up to become the large galaxies we see today. They would have to change a lot over 11 billion years, growing five times bigger. They could get larger by colliding with other galaxies, but such collisions may not be the complete answer.”

To determine the sizes of the galaxies, the team used the Near Infrared Camera and Multi-Object Spectrometer on Hubble. The Keck observations were carried out with assistance of a powerful laser to correct for image blurring caused by the Earth’s atmosphere. “Only Hubble and Keck can see the sizes of these galaxies because they are very small and far away,” van Dokkum explained.

Van Dokkum and his colleagues studied the galaxies in 2006 with the Gemini South Telescope Near-Infrared Spectrograph, on Cerro Pachon in the Chilean Andes. Those observations provided the galaxies’ distances and showed that the stars are a half a billion to a billion years old. The most massive stars had already exploded as supernovae.

“In the Hubble Deep Field, astronomers found that star-forming galaxies are small,” said Marijn Franx of Leiden University, The Netherlands. “However, these galaxies were also very low in mass. They weigh much less than our Milky Way. Our study, which surveyed a much larger area than in the Hubble Deep Field, surprisingly shows that galaxies with the same weight as our Milky Way were also very small in the past. All galaxies look really different in early times, even massive ones that formed their stars early.”

The ultradense galaxies might comprise half of all galaxies of that mass 11 billion years ago, van Dokkum said, forming the building blocks of today’s largest galaxies.

How did these small, crowded galaxies form? One way, suggested van Dokkum, involves the interaction of dark matter and hydrogen gas in the nascent universe. Dark matter is an invisible form of matter that accounts for most of the universe’s mass. Shortly after the Big Bang, the universe contained an uneven landscape of dark matter. Hydrogen gas became trapped in puddles of the invisible material and began spinning rapidly in dark matter’s gravitational whirlpool, forming stars at a furious rate.

Based on the galaxies’ masses, which are derived from their color, the astronomers estimated that the stars are spinning around their galactic disks at roughly 890,000 to 1 million miles an hour (400 to 500 kilometers a second). Stars in today’s galaxies, by contrast, are traveling at about half that speed because they are larger and rotate more slowly than the compact galaxies.

These galaxies are ideal targets for the Wide Field Camera 3, which is scheduled to be installed aboard Hubble during Servicing Mission 4 in the fall of 2008. “We hope to use the Wide Field Camera 3 to find thousands of these galaxies. The Hubble images, together with the laser guide star adaptive optics system at Keck Observatory, should lead to a better understanding of the evolution of galaxies early in the life of the universe,” said Garth Illingworth of the University of California, Santa Cruz, and Lick Observatory.

The findings appeared in the April 10 issue of
The Astrophysical Journal Letters....

The authors of the science paper are Pieter van Dokkum (Yale University), Marijn Franx (Leiden University, The Netherlands), Mariska Kriek (Princeton University), Bradford Holden, Garth Illingworth, Daniel Magee, and Rychard Bouwens (University of California, Santa Cruz and Lick Observatory), Danilo Marchesini (Yale University), Ryan Quadri (Leiden University), Greg Rudnick (National Optical Astronomical Observatory, Tucson), Edward Taylor (Leiden University), and Sune Toft (European Southern Observatory, Germany).

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency (ESA) and is managed by NASA’s Goddard Space Flight Center (GSFC) in Greenbelt, Md. The Space Telescope Science Institute (STScI) conducts Hubble science operations. The institute is operated for NASA by the Association of Universities for Research in Astronomy, Inc., Washington, DC.

The W. M. Keck Observatory (http://www.keckobservatory.org) is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. Made possible by grants totaling $138 million from the W. M. Keck Foundation, the Observatory began operations in 1992 and today has a base budget of $12 million, augmented by various grants, contracts and private donations which totaled $14M in FY07.

Water Vapor Detected in Protoplanetary Disks

PASADENA, Calif.—Water is an essential ingredient for forming planets, yet has remained hidden from scientists searching for it in protoplanetary systems, the spinning disks of particles surrounding newly formed stars where planets are born. Now the detection of water vapor in the inner part of two extrasolar protoplanetary disks brings scientists one step closer to understanding water’s role during terrestrial planet formation.

By maximizing the spectroscopic capabilities of NASA’s Spitzer Space Telescope and high-resolution measurements from the Keck II Telescope in Hawaii, researchers from the California Institute of Technology and other institutes found water molecules in disks of dust and gas around two young stars. DR Tau and AS 205A, respectively around 457 and 391 light-years away from Earth, are each at the center of a spinning disk of particles that may eventually coalesce to form planets.

“This is one of the very few times that water vapor has been detected in the inner part of a protoplanetary disk—the most likely place for terrestrial planets to form,” says Colette Salyk, a graduate student in geological and planetary sciences at Caltech. She is the lead author of a group of scientists reporting their findings in the March 20 issue of the Astrophysical Journal Letters.

Salyk and her colleagues first harnessed light-emission data captured by Spitzer to inspect dozens of young stars with protoplanetary disks. They honed in on DR Tau and AS 205A because these presented a large number of water emission lines—spikes of brightness at certain wavelengths that are a unique fingerprint for water vapor. “Only Spitzer is capable of observing these particular lines in a large number of disks because it operates above Earth’s obscuring water-vapor-rich atmosphere,” says Salyk.

To determine in what part of the disk the vapor resides, the team made high-resolution measurements at shorter wavelengths with NIRSPEC, the Near-InfraRed cross-dispersed echelle grating Spectrometer for the Keck II Telescope. Unlike Spitzer, which observed water lines blended together into clumps, NIRSPEC can resolve individual water lines in selected regions where the atmospheric transmission is good. The shape of each line relays information on the velocity of the molecules emitting the light. “They were moving at fast speeds,” says Salyk, “indicating that they came from close to the stars, which is where Earthlike planets might be forming.”

“While we don’t detect nearly as much water as exists in the oceans on Earth, we see only a very small part of the disk—essentially only its surface—so the implication is that the water is quite abundant,” remarks coauthor Geoffrey Blake, professor of cosmochemistry and planetary sciences and professor of chemistry at Caltech.

The presence of water in the inner disk may indicate its stage on the road to planet formation. A planet like Jupiter in our solar system grew as its gravitational field trapped icy solids spinning in the outer part of the sun’s planetary disk. However, before Jupiter gained much mass, these same icy solids could have traveled towards the star and evaporated to produce water vapor such as that seen around DR Tau and AS 205A.

Although they have not detected icy solids in the extrasolar disks, says Salyk, “our observations are possible evidence for the migration of solids in the disk. This is an important prediction of planet-forming models.”

These initial observations portend more to come, says coauthor Klaus Pontoppidan, a Caltech Hubble Postdoctoral Scholar in Planetary Science. “We were surprised at how easy it is to find water in planet-forming disks once we had learned where to look. It will take years of work to understand the details of what we see.”

This is “a much larger story than just one or two disks,” Blake adds. “With upcoming observations of tens of young stars and disks with both Spitzer and NIRSPEC, along with our data in hand, we can construct a story for how water concentrations evolve in disks, and hopefully answer questions like how Earth acquired its oceans.”

Contact: Elisabeth Nadin (626) 395-3631 .(JavaScript must be enabled to view this email address)

NOVA PHENOMENON EXPLAINED WITH NULLING MODE AT KECK OBSERVATORY

MAUNA KEA (January 28th, 2008) First results from a new scientific instrument at W. M. Keck Observatory are helping scientists understand the physics behind recurrent novae, a type of cataclysmic star system. The results are overturning long-standing assumptions about powerful explosions called novae and have produced the first unified model for a nearby nova called RS Ophiuchi.

“We were getting ready for a routine engineering run when all of a sudden the nova went off. It was very bright and easy to observe, so we took this opportunity and turned it into gold,” says team member Marc Kuchner of NASA’s Goddard Space Flight Center in Greenbelt, Md.

The “nulling” mode of the Keck Interferometer is part of the NASA-funded Keck Interferometer, which combines starlight using two 10-meter (33 feet) telescopes. In this mode, the interferometer suppresses the blinding light of a star so researchers can study the surrounding environment. The instrument helps researchers observe very faint objects near bright sources and produces ten times more resolving power than a single Keck telescope working alone. It is the only instrument of its kind in operation.

The nulling mode was developed to search for dust around nearby stars, which make finding planets around these stars more difficult. “If the dust were by itself, it would be easy to detect with Keck,” explains Dr. Rachel L. Akeson, Keck Interferometer project scientist at the Michelson Science Center at Caltech. “But the star is so much brighter, that something has to be done to block the light, which is what the nuller does. But this technique turns out to be useful for lots of other kinds of objects, including this one, where dust is near a star that just went nova.”

The Keck Nuller was undergoing tests February 12, 2006, when a nova flared up in the constellation Ophiuchus. The system, known as RS Ophiuchi, consists of a white dwarf and a red giant. The red giant is gradually shedding its massive gaseous outer layers, and the white dwarf is sweeping up much of this wind, growing in mass over time. As the matter builds up on the white dwarf’s surface it eventually reaches a critical point that ignites a thermonuclear explosion that causes the system to brighten 600-fold. RS Ophiuchi was previously seen to blow its stack in 1898, 1933, 1958, 1967, and 1985, so astronomers were eagerly anticipating the 2006 eruption.

Just 3.8 days after the nova was detected, the group observed the explosion with the Keck Nuller. The team set the instrument to cancel out the nova’s light, allowing the group to see the much fainter surrounding material. The group next adjusted the nuller to observe the extremely bright blast zone.

The instrument’s versatility was key to a surprising discovery. The nuller saw no dust in the bright zone, presumably because the nova’s blast wave vaporized dust particles. But farther from the white dwarf, at distances starting around 20 times the Earth-Sun distance, the nuller recorded the spectral signature of silicate dust. The blast wave had not yet reached this zone, so the dust must have pre-dated the explosion.

“This flies in the face of what we expected. Astronomers had previously thought that nova explosions actually create dust,” says Richard Barry of NASA Goddard, lead author of a paper on the Keck observations that will be published in the Astrophysical Journal. The team thinks the dust is created as the white dwarf plows through the red giant’s wind, creating a pinwheel pattern of higher-density regions that is reminiscent of galaxy spiral arms. Inside these spiral arms, atoms reach low enough temperatures and high enough densities to allow atoms to stick together to form dust particles. The nova’s blast wave has since destroyed RS Ophiuchi’s pinwheel pattern, but it should re-form over the next few years, and future Spitzer Space Telescope observations could see it.

Most studies of RS Ophiuchi have relied on spectroscopic models, but those methods have not been able to distinguish various nova components with as much detail as the interferometer. The Keck Nuller measured one component of the RS Ophiuchi system to an accuracy of just 4 milliarcseconds, or about the size of a basketball at 7,500 miles. The findings led to a new physical model of the system.

Barry is also coauthor of a paper based on Spitzer observations of RS Ophiuchi. This paper, which appeared in the December 20, 2007 issue of Astrophysical Journal, reports independent evidence for silicate dust that predates the 2006 explosion.

“The RS Ophiuchi observations are just a small taste of the power and potential we expect from the Keck Nuller,” says coauthor William Danchi of NASA Goddard. “But ultimately we want to launch a nulling interferometer into space to image extrasolar planets. These Keck results are a technological and scientific pathfinder toward that future.”

The paper, “Milliarcsecond N-Band Observations of the Nova RS Ophiuchi: First Science with the Keck Interferometer Nuller” will be published in the May 1st issue of the Astrophysical Journal, with co-authors from Goddard, Jet Propulsion Laboratory, Michelson Science Center, W. M. Keck Observatory and Columbia University.

Observations were conducted at the W. M. Keck Observatory (http://www.keckobservatory.org) in Hawaii, a non-profit 501 (c) (3) organization. The Michelson Science Center manages the Keck Interferometer’s science operations for NASA’s Science Mission Directorate from its offices at Caltech in coordination with the Jet Propulsion Laboratory. The W. M. Keck Observatory is governed by a board of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles. For more information about the Keck Interferometer Nuller, visit: http://msc.caltech.edu/ missions/KI/.

Astrophysical Journal preprint: Milliarcsecond N-Band Observations of the Nova RS Ophiuchi: First Science with the Keck Interferometer Nuller

NASA Mega-Telescope Gears Up to Study Cosmos

(December 5th, 2007) NASA has selected three teams of scientists to begin studying disks of dust around nearby stars starting in February 2008, using the Keck Interferometer in Mauna Kea, Hawaii. This sophisticated new system combines the observing power of the two large Keck telescopes into a single mega-telescope.

The announcement follows completion of the Keck Interferometer’s technology phase, in which its detectors, starlight trackers, active optics and computer control systems were installed, tested and integrated. Testing was conducted on stars, in the first on-sky demonstration of long-baseline nulling interferometry, a technique that “cancels” the bright light from the star to see fainter material around it.

The newly selected teams are led by the following principal investigators:
• Phil Hinz, University of Arizona, Tucson, Ariz.
• Marc Kuchner, Goddard Space Flight Center, Greenbelt, Md.
• Eugene Serabyn, Jet Propulsion Laboratory, Pasadena, Calif.

The teams will study stars with known debris disks and look for signs of dust around other stars. Some debris disks are remnants from planet formation; others contain material kicked up when asteroids collide. Asteroid collisions in our solar system produce a disk of what’s called “zodiacal dust.” This can be seen when sunlight scatters small dust grains to produce a faint band of light visible against a dark sky just after sunset or before dawn. The Keck Interferometer science teams are looking for comparable, although much brighter, disks in other planetary systems.

The Keck Interferometer links the Keck Observatory’s two 10-meter (33-foot) telescopes. It is part of NASA’s ongoing quest to search for planets orbiting other stars. JPL, a division of the California Institute of Technology in Pasadena, manages the Keck Interferometer for NASA. The Keck Interferometer was developed by JPL, the W.M. Keck Observatory and the Michelson Science Center at Caltech. The W.M. Keck Observatory is funded by Caltech, the University of California and NASA, and is managed by the California Association for Research in Astronomy, Kamuela, Hawaii.

More information on the Keck Interferometer is at http://planetquest.jpl.nasa.gov/Keck/keck_index.cfm. Click “Visualizations” for a virtual tour and animation.

Keck Helps Discover Record Fifth Planet

Berkeley (November 6th, 2007) A team of American astronomers announced the discovery of a record-breaking fifth planet around the nearby star 55 Cancri, making it the only star aside from the sun known to have five planets.

The discovery comes after 19 years of observations of 55 Cancri and represents a milestone for the California and Carnegie Planet Search team, which this year celebrates the 20th anniversary of its first attempts to find extrasolar planets by analyzing the wobbles they cause in their host star.

The team’s long history of measurements - more than 300 for 55 Cancri alone - made the discovery of a five-planet system possible, said UC Berkeley astronomy professor Geoffrey Marcy, who with Paul Butler, now at the Carnegie Institution of Washington, began observations of many nearby stars at the University of California Lick Observatory in 1987.

The unique 55 Cancri system, located 41 light-years away in the direction of the constellation Cancer, is notable also because its clutch of four inner planets and one giant outer planet resembles our own solar system, though without an Earth or Mars.

“This system is interesting because there’s a giant planet at 6 AU and four smaller planets inward of 0.8 AU, with a huge remaining gap in between, right where we would expect to find an Earth-sized planet,” Marcy said.

An AU, or astronomical unit, is the average distance between the Earth and the sun, about 93 million miles.

According to lead author Debra Fischer, assistant professor of astronomy at San Francisco State University, the fifth planet is within the star’s habitable zone in which water could exist as a liquid. Though the planet is a giant ball of gas, liquid water could exist on the surface of a moon or on other, rocky planets that may yet be found within the zone. “Right now, we are looking at a gap between the 260-day orbit of the new planet and the 14-year orbit of another gas giant, and if you had to bet, you’d bet that there is more orbiting stuff there.”

Fischer noted that what occupies this gap has to be another planet around the size of Neptune or smaller, because anything larger would have destabilized the orbits of the other planets. All of the planets around 55 Cancri are in stable, nearly circular obits, like the eight planets in our solar system. Jupiter is located at 5.2 AU from the sun, while Mercury and Venus are closer than 0.72 AU. Earth and Mars are in the gap at 1 AU and 1.5 AU.

“We haven’t found a twin of our solar system, because the four planets close to the star are all the size of Neptune or bigger,” Marcy said, but he added that he’s optimistic that continued observations will reveal a rocky planet within five years.

The new discovery, using data from the Lick Observatory and the W. M. Keck Observatory in Hawaii, has been accepted for publication in the Astrophysical Journal. The authors are Fischer, Marcy and their colleagues at the Carnegie Institution, San Francisco State University, UC Santa Cruz, Tennessee State University and UC Berkeley.

Fischer and Marcy also discussed their findings today during a media teleconference hosted by NASA.

In 1996, when Marcy and Butler found a Jupiter-sized planet orbiting close to 55 Cancri and circling every 14.6 days, it was only the fourth known star with an exoplanet. The second planet discovered around the star, in 2002, turned out to circle in a more distant orbit, like our own Jupiter does, although the planet was four times the weight of Jupiter. The third, also discovered in 2002, was smaller, about half the size of Saturn, and was orbiting near the star with an orbit of 44 days, slightly farther than the first planet. The fourth planet, found in 2004, was so close to the star as to be hellishly hot - a Neptune-sized planet (14 times Earth’s mass) with a 2.8 day period discovered in collaboration with a team led by Barbara McArthur of the University of Texas.

Although astronomers have found nearly 250 exoplanets, only one other star, mu Ara in the southern sky, is known to have four planets.

The newly-found fifth planet around 55 Cancri is also large - around half the size of Saturn, or at least 45 times the mass of Earth - and orbiting at about 0.785 AU in 260.8 days. Because the star 55 Cancri is older and dimmer than our sun, the habitable zone - the region in which planetary temperatures can be favorable for liquid water - is closer to the star than is our sun’s habitable zone, and includes the new planet.

Finding multiple planets around a star is difficult because each planet produces its own stellar wobble. Marcy compares detecting the wobble within wobbles that are caused by one of several planets to picking out a single musical note from many played simultaneously. While the ear can do that, it took Marcy more than 10 months to convince himself that a fifth wobble was buried in the data.

The Doppler technique used by the search team sees this wobble as a change in the speed with which a star moves toward or away from us. The search team can detect velocities as small as 1 meter per second, which is walking speed.

55 Cancri has produced “a rat’s nest of radial velocity data,” Fischer said. “We probably still don’t have all the planets. We are pulling out one thread at a time, disentangling all these orbits, and it has taken a lot more data and time than we predicted. I think it’s amazing what we have been able to do with the system.”

Coauthors with Fischer, Marcy and Butler are Steven S. Vogt and Greg Laughlin of UC Santa Cruz; Jason T. Wright, John A. Johnson and Kathryn M. G. Peek of UC Berkeley; Gregory W. Henry of Tennessee State University’s Center of Excellence in Information Systems; and David Abouav, Chris McCarthy and Howard Isaacson of San Francisco State University.

The work was supported by the University of California, NASA and the National Science Foundation.

Press Release Courtesy UC Berkeley

Morning forecast on Titan calls for widespread methane drizzle off Xanadu, according to Keck, VLT im

(October 11th, 2007) Berkeley — Noted for its bizarre hydrocarbon lakes and frozen methane clouds, Saturn’s largest moon, Titan, also appears to have widespread drizzles of methane, according to a team of astronomers at the University of California, Berkeley.

New near-infrared images from Hawaii’s W. M. Keck Observatory and Chile’s Very Large Telescope show for the first time a nearly global cloud cover at high elevations and, dreary as it may seem, a widespread and persistent morning drizzle of methane over the western foothills of Titan’s major continent, Xanadu.

In most of the Keck and VLT images, liquid methane clouds and drizzle appear at the morning edge of Titan, the arc of the moon that has just rotated into the light of the sun.

“Titan’s topography could be causing this drizzle,” said Imke de Pater, UC Berkeley professor of astronomy. “The rain could be caused by processes similar to those on Earth: Moisture laden clouds pushed upslope by winds condense to form a coastal rain.”

Lead author Mate Adamkovics, a UC Berkeley research astronomer, noted that only areas near Xanadu exhibited morning drizzle, and not always in the same spot. Depending on conditions, the drizzle could hit the ground or turn into a ground mist. The drizzle or mist seems to dissipate after about 10:30 a.m. local time, which, because Titan takes 16 Earth days to rotate once, is about three Earth days after sunrise.

“Maybe only Xanadu has misty mornings,” he said.

Adamkovics, de Pater and their colleagues in UC Berkeley’s Center for Integrative Planetary Studies report their observation in the Oct. 11 issue of Science Express, an online version of the journal Science. They also will present their findings during a noon EDT press conference on Oct. 11 at the Division for Planetary Sciences meeting of the American Astronomical Society in Orlando, Fla.

Titan, larger than the planet Mercury, is the only moon in the solar system with a thick atmosphere, which is comprised mostly of nitrogen and resembles Earth’s early atmosphere. Previous observations have shown that the entire moon is swathed in a hydrocarbon haze extending as high as 500 kilometers, becoming thinner with height. The south pole area exhibits more haze than elsewhere, with a hood of haze at an altitude between 30 and 50 kilometers.

Because of its extremely cold surface temperature – minus 183 degrees Celsius (-297 degrees Fahrenheit) – trace chemicals such as methane and ethane, which are explosive gases on Earth, exist as liquids or solids on Titan. Some level features on the surface near the poles are thought to be lakes of liquid hydrocarbon analogous to Earth’s watery oceans, and presumably these lakes are filled by methane precipitation. Until now, however, no rain had been observed directly.

“Widespread and persistent drizzle may be the dominant mechanism for returning methane to the surface from the atmosphere and closing the methane cycle,” analogous to Earth’s water cycle, the authors wrote.

Actual clouds on Titan were first imaged in 2001 by de Pater’s group and colleagues at Caltech using the Keck II telescope with adaptive optics and confirmed what had been inferred from spectra of Titan’s atmosphere. These frozen methane clouds hovered at an elevation of about 30 kilometers around Titan’s south pole.

Since then, isolated ethane clouds have been observed at the north pole by NASA’s Cassini spacecraft, while both Cassini and Keck photographed methane clouds scattered at mid-southern latitudes. Also in 2005, the Huygens probe, build by the European Space Agency and released by Cassini, plummeted through Titan’s atmosphere, collecting data on methane relative humidity. These data provided evidence for frozen methane clouds between 25 and 30 kilometers in elevation and liquid methane clouds – with possible drizzle – between 15 and 25 kilometers high. The extent of the clouds detected in the descent area was unclear, however, because “a single weather station like Huygens cannot characterize the meteorology on a planet-wide scale,” said UC Berkeley research astronomer Michael H. Wong.

The new images show clearly a widespread cloud cover of frozen methane at a height of 25 to 35 kilometers – “a new type of cloud, a big global cloud of methane,” Adamkovics said – that is consistent with Huygens’ measurements, plus liquid methane clouds in the tropopause below 20 kilometers with rain at lower elevations.

Because earlier observers thought that the methane droplets in these clouds were too sparse to be seen, they referred to the frozen and liquid methane clouds as “sub-visible.”

“The stratiform clouds we see are like cirrus clouds on Earth,” Adamkovics said. “One difference is that the methane droplets are predicted to be at least millimeter-sized on Titan, as opposed to micron-sized in terrestrial clouds – a thousand times smaller. Since the clouds have about the same moisture content as Earth’s clouds, this means the droplets on Titan are much more spread out and have a lower density in the atmosphere, which makes the clouds ‘subvisible’ and thus hard to detect.”

If all the moisture were squeezed out of Titan’s clouds, it would amount to about one and a half centimeters (six-tenths of an inch) of liquid methane spread around Titan’s surface, Adamkovics said. This is about the same moisture content as some of Earth’s clouds.

Since 1996, de Pater and colleagues have been using infrared detectors on the Keck telescopes to regularly monitor clouds and hazes on Titan. In past years, they have also used the VLT. The advantage of observing at infrared wavelengths is that Titan’s haze is relatively transparent. At optical wavelengths, these haze layers form an impenetrable layer of photochemical smog.

By observing at different infrared wavelengths, scientists can probe different altitudes in Titan’s atmosphere, depending on the strength of the methane absorption at that wavelength. Then, by using the methane absorption profile, they can pinpoint particular altitudes in Titan’s atmosphere, allowing astronomers to see the surface and judge the altitude of methane clouds. Adamkovics first saw evidence of widespread, cirrus-like clouds and methane drizzle when analyzing Feb. 28, 2005, data from a new instrument on the European Southern Observatory’s VLT – the Spectrograph for INtegral Field Observations in the Near Infrared (SINFONI).

Sharper images and spectra taken on April 17, 2006, by the OH-Suppressing Infra-Red Imaging Spectrograph (OSIRIS) on Keck II confirmed the clouds. Both instruments measure spectra of light at many points in an image rather than averaging across the entire image. By subtracting light reflected from the surface from the light reflected by the clouds, the researchers were able to obtain images of the clouds covering the entire moon.

“Once we saw this in both data sets, we altered our radiative transfer models for Titan and recognized that the only way to explain the data was if there was liquid or solid methane in the atmosphere,” Adamkovics said. “This is a big step in helping us understand the extent to which solid clouds and liquids are spread throughout Titan’s atmosphere.”

UC Berkeley graduate student Conor Laver is the fourth author on the Science Express paper. The work was supported by the National Science Foundation and Technology Center for Adaptive Optics (CfAO), NASA and the Center for Integrative Planetary Science (CIPS) at UC Berkeley.

Scientists ‘Weigh’ Tiny Galaxy Halfway Across Universe

(October 4th, 2007) Santa Barbara, California –– A tiny galaxy, nearly halfway across the universe, the smallest in size and mass known to exist at that distance, has been identified by an international team of scientists led by two from the University of California, Santa
Barbara.

The scientists used data collected by NASA’s Hubble Space Telescope and the W. M. Keck Observatory in Hawaii. This galaxy is about half the size, and approximately one-tenth the “weight” of the smallest distant galaxies typically observed, and it is 100 times lighter than our own Milky Way.

The findings will be published in the December 20, 2007 issue of the Astrophysical Journal.

The article is now available on-line at http://arxiv.org/abs/0710.0637.

“Even though this galaxy is more than six billion light years away, the reconstructed image is as sharp as the ordinary ground-based images of the nearest structure of galaxies, the Virgo cluster, which is 100 times closer to us,” said lead author Phil Marshall, a postdoctoral fellow at UC Santa Barbara.

Second author Tommaso Treu, assistant professor of physics at UCSB, explained that the imaging is made possible by the fact that the newly discovered galaxy is positioned behind a
massive galaxy, creating an “Einstein ring.” The matter distribution in the foreground bends
the light rays in much the same way a magnifying glass does. By focusing the light rays, this gravitational lensing effect increases the apparent brightness and size of the background galaxy by more than a factor of 10.

Treu and his colleagues in the Sloan Lens ACS Survey (SLACS) collaboration
(http://www.slacs.org) are at forefront of the study of Einstein ring gravitational lenses.

With gravitational lensing, light from distant galaxies is deflected on its way to Earth by the gravitational field of any massive object that lies in the way. Because the light bends, the galaxy is distorted into an arc or multiple separate images. When both galaxies are exactly lined up, the light forms a bull’s-eye pattern, called an Einstein ring, around the foreground galaxy. See: http://www.ia.ucsb.edu/pa/display.aspx?pkey=1380.

The mass estimate for the galaxy, and the inference that many of its stars have only
recently formed, is made possible by the combination of optical and near infrared images from the Hubble Space Telescope with longer wavelength images obtained with the Keck Telescope. “If the galaxy is representative of a larger population, it could be one of the
building blocks of today’s spiral galaxies, or perhaps a progenitor of modern dwarf galaxies,” said Treu. ” It does look remarkably similar to the smallest galaxies in the Virgo cluster, but is almost half the way across the universe.”

Another key aspect of the research is the use of “laser guide star adaptive optics.” Adaptive optics systems use bright stars in the field of view to measure the Earth’s
atmospheric blurring and correct for it in real time. This technique relies on having a bright star in the image as well, so it is limited to a small fraction of the night sky. The laser guide star adaptive optics system in place at the Keck Telescope uses a powerful laser
to illuminate the layer of sodium atoms that exist in the Earth’s atmosphere, explained
Jason Melbourne, a team member from the Center for Adaptive Optics at the University of
California, Santa Cruz. The laser image acts as an artificial star, bright enough to perform adaptive optics correction at an arbitrary position in the sky, thus enabling much sharper imaging over most of the sky. For more on this topic see: http://keckobservatory.org/index.php/news/laser_guide_star_available_for_adaptive_optics/.

Marshall’s postdoctoral fellowship research is funded by the TABASGO Foundation through
UCSB. Treu’s research is supported by the National Aeronautical and Space Administration (NASA), the National Science Foundation, and the Sloan Foundation.

Other researchers involved in the project are: Raphael Gavazzi of UC Santa Barbara; Kevin
Bundy of the University of Toronto; S. Mark Ammons of Lick Observatory and the Center for Adaptive Optics (CfAO) at the University of California, Santa Cruz; Adam S. Bolton of the
Institute for Astronomy at the University of Hawaii; Scott Burles of the Massachusetts
Institute of Technology; James Larkin of the University of California, Los Angeles; David Le
Mignant of the W. M. Keck Observatory and CfAO at UC Santa Cruz; David C. Koo of the Lick Observatory at UC Santa Cruz; Leon V.E.Koopmans of the Kapteyn Astronomical Institute, the Netherlands; Claire E. Max of the Lick Observatory and CfAO at UC Santa Cruz; Leonidas A. Moustakas of the Jet Propulsion Laboratory and the California Institute of Technology; Eric Steinbring of the Herzberg Institute of Astrophysics, National Research Council of Canada; and Shelly A. Wright of UCLA.

Dark, but Light: Smallest Galaxies Ever Seen Solve a Big Problem

Mauna Kea (September 12th, 2007) Mauna Kea scientists may have solved a discrepancy between the number of extremely small, faint galaxies predicted to exist near the Milky Way and the number actually observed. In an attempt to resolve the “Missing Dwarf Galaxy” problem, two astronomers used the W. M. Keck Observatory to study a population of the darkest, most lightweight galaxies known, each containing 99% dark matter. The findings suggest the “Missing Dwarf Galaxy” problem is not as severe as previously thought, and may have been solved completely.

“It seems that very small, ultra-faint galaxies are far more plentiful than we thought,” said Dr. Marla Geha, co-author of the study and a Plaskett Research Fellow at the Herzberg Institute of Astrophysics in Canada. “If you asked me last year whether galaxies this small and this dark existed, I would have said no. I’m astonished that so many tiny, dark matter-dominated galaxies have now been discovered.”

The Missing Dwarf Galaxy puzzle comes from a prediction of the “Cold Dark Matter” model, which explains the growth and evolution of the universe. It predicts large galaxies like the Milky Way should be surrounded by a swarm of up to several hundred smaller galaxies known as “dwarf galaxies.” However, until recently, only 11 such companions were known to be orbiting the Milky Way. To explain this large discrepancy, theorists suggested that while hundreds of dwarf galaxies near the Milky Way may indeed exist, the majority might have few, if any, stars. If so, the galaxies would be comprised almost entirely of dark matter—a mysterious type of matter that has gravitational effects on ordinary atoms, but which does not produce any light. But proving the existence of a large number of nearly invisible galaxies seemed problematic, until now.

Dr. Josh Simon, a Millikan Postdoctoral Scholar at the California Institute of Technology, and Dr. Geha used the 10-meter Keck II telescope with the DEIMOS spectrograph to conduct follow-up studies of eight new dwarf galaxies first discovered with the Sloan Digital Sky Survey. The results enabled the duo to calculate precisely the total mass of each galaxy. To their surprise, each system was among the smallest ever measured, more than 10,000 times smaller than the Milky Way.

“The formation of such small galaxies is not very well understood from a theoretical perspective,” said Dr. Simon. “Explaining how stars form inside these remarkably tiny galaxies is difficult, and so it is hard to predict exactly how many dwarfs we should find near the Milky Way. Our work narrows the gap between the Cold Dark Matter theory and observations by significantly increasing the number of Milky Way dwarf galaxies and telling us more about the properties of these galaxies. We also now know that dwarf galaxies can be even smaller than we thought possible.”

Numerous, repeated measurements of 814 stars in the eight dwarf galaxies were obtained at W. M. Keck Observatory. The stars were found to be moving much slower than stars in any other known galaxy (about 4 to 7 km/sec.) For comparison, the Sun orbits the center of the Milky Way at a speed of about 220 km/sec. In all, the astronomers measured precise speeds for 18 to 214 stars in each galaxy, about three times more stars per galaxy than any previous study.

“This is a significant paper,” said Dr. Taft Armandroff, director of the W. M. Keck Observatory, whose own research includes the study of dwarf galaxies. “It is a compelling example of how large, ground-based telescopes can precisely measure the orbits of distant stars on the sky to just a few kilometers per second. I expect DEIMOS will soon tell us about the chemical composition of these stars to help us better understand how star formation takes place in such small galaxies.”

Some parameters of the Cold Dark Matter theory can now be updated to match observed conditions in the local universe. Based on the masses measured for the new dwarf galaxies, Drs. Simon and Geha concluded the fierce ultraviolet radiation given off by the first stars, which formed just a few hundred million years after the Big Bang, may have blown all of the hydrogen gas out of the dwarf galaxies forming at that time. The loss of gas prevented the galaxies from creating new stars, leaving them very faint, or in many cases completely dark. When this effect is included in theoretical models, the numbers of expected and observed dwarf galaxies agree.

“One of the implications of our results is that up to a few hundred completely dark galaxies really should exist in the Milky Way’s cosmic neighborhood,” said Dr. Geha. “If the Cold Dark Matter model is correct they have to be out there, and the next challenge for astronomers will be finding a way to detect their presence.”

Because the Sloan Digital Sky Survey only covered about 25 percent of the sky, future surveys of the remainder of the sky are expected to discover as many as 50 more dark matter dominated dwarf galaxies orbiting the Milky Way. Telescopes for one such survey, the Pan-STARRS project on Maui, are now under construction.

The paper, “Kinematics of the Ultra-Faint Milky Way Satellites: Solving the Missing Satellite Problem,” will be published in the November 10 issue of the Astrophysical Journal. Funding for the project was provided by the California Institute of Technology under the Millikan Fellowship program and the Herzberg Institute of Astrophysics of the National Research Council of Canada. Data reduction software was made possible by the support of the National Science Foundation (AST 0071048).

Observations were conducted at the W. M. Keck Observatory (http://www.keckobservatory.org) in Hawaii, a non-profit 501 (c) (3) organization. The governing board of Keck Observatory consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

‘One Of The Most Curious Objects In The Sky’ Delights Astronomers Again

Mauna Kea (August 29th, 2007) Edwin Hubble once called IC 10 “one of the most curious objects in the sky,” and new observations of the extremely faint, lightweight dwarf galaxy are giving scientists new clues about how populations of stars are born.

Though the properties of stars is one of the most well-studied topics in astronomy, scientists still don’t fully understand all the mechanisms involved in star formation and evolution, particularly in galaxies with low levels of oxygen, nitrogen and other heavy elements. But scientists studying the IC 10 galaxy may soon understand how stars might have looked like in the distant past, when the universe was in a younger, more pristine form.

“A few years ago these types of studies would have been impossible from the ground,” said Dr. Taft Armandroff, director of the W. M. Keck Observatory, who’s own research includes the study of dwarf galaxies. “We can now study individual stars of galaxies several million light years from Earth to understand how star formation events may have affected the evolution of the Milky Way galaxy. This galaxy can teach us what the most common types of galaxies in the universe might be like.”

New images of IC 10 reveal a small region of space teeming with nearly a thousand stars. The image, obtained with NASA’s Hubble Space Telescope and the W. M. Keck Observatory in Hawaii, shows evidence of a vigorous star formation event that took place within the last 10 million years.

Dr. William Vacca at the NASA Ames Research Center led the study and says IC 10 may answer many unresolved questions about stellar evolution. “IC 10 is a remarkable galaxy,” he said. “It is the only one we’ve seen that falls outside an established pattern of having a certain number of massive nitrogen-type stars for each carbon-type star. This imbalance has caused us to wonder if our past conclusions about massive stars have been correct. Do we need to revise the models of stellar evolution?”

Astronomers have known that IC 10 has more giant, rare stars called “Wolf-Rayet stars” than all other nearby dwarf galaxies combined. Wolf-Rayet stars are extremely hot blue stars losing enormous amounts of mass to the interstellar medium. In addition, the proportion of Wolf-Rayet stars in IC 10 seems to be wildly out of balance. For the number of stars containing carbon, astronomers expected to see a certain number containing nitrogen. But so far, very few nitrogen stars have been found. Could IC 10 be hiding a population of stars?

Using a combination of Hubble and Keck telescope images, Vacca’s team found many previously undiscovered stars in the IC 10 galaxy. Each new star can now be measured to determine its chemical composition. If the newly found stars contain nitrogen, then part of the “missing nitrogen” puzzle might be solved.

“The combination of HST images in the optical and Keck Laser Guide Star images in the infrared has been a major breakthrough in our understanding of dense stellar regions,” said co-author Dr. James R. Graham, professor of astronomy at UC Berkeley. “IC 10 has so many stars in such a tiny region of space that ground-based studies have been confused. But the combination of HST and Keck has been revolutionary in our understanding of this object, and for any object with a dense region of stars.”

The new images of IC 10 are centered on a bright star first thought to possibly be the most luminous Wolf-Rayet star in IC 10. Follow up studies then found the star to be comprised of at least three or more components. Now, new data from Keck show the bright star ([MAC92] 24) is actually six or more stars, perhaps even a cluster of stars.

“This is the first time this sort of study has been done using adaptive optics,” said co-author Christopher Sheehy of the University of Chicago. “It gives us the ability to make these kinds of measurements accurately from the ground and there’s no shortage of targets in need of a fresh look. The potential is exciting.”

The new data has also enabled scientists to measure the precise distance to IC 10, a figure that has eluded scientists since the object’s discovery more than 100 years ago. Dr. Vacca and his collaborators calculated the distance to IC 10 to be about 2.6 million light years from Earth, or 800 kiloparsecs. This is in good agreement with some previous estimates.

IC 10 was first discovered by Lewis Swift in 1889 at the Warner Observatory in Rochester, New York. The “Index Catalogue” (IC) is a catalogue of galaxies, nebulae and star clusters that supplements the more modern New General Catalogue (NGC). First published in 1895, the catalogue first described IC 10 as a “faint star involved in extremely faint and very large nebula.” It wasn’t until 1935 that IC 10 was first proposed as an extragalactic object and Edwin Hubble later proposed IC 10 might be a member of the Local Group. It took another 30 years before these suspicions could be confirmed using radial velocity and distance measurements.

Astronomers now know IC 10 is similar in many ways to the Large Magellenic Cloud of the Southern Hemisphere. But unlike the Large Magellenic Cloud, IC 10 orbits Andromeda, not the Milky Way. The study of IC 10 is giving astronomers a picture of what the Milky Way might have looked like billions of years ago before the galaxy’s interstellar medium was enriched with elements such as oxygen and nitrogen.

The paper, “Imaging of the Stellar Population of IC 10 with Laser Guide Star Adaptive Optics and the Hubble Space Telescope,” was published in the June 10 issue of Astrophysical Journal. The research was made possible with grants provided by the National Science Foundation (AST 0205999 and AST 9876783) and NASA.

The W. M. Keck Observatory (http://www.keckobservatory.org) is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

Scientists Study Changes In Planets Rings

Berkeley (August 23rd, 2007) As the rings of Uranus swing edge-on to Earth – a short-lived view we get only once every 42 years – astronomers observing the event are getting an unprecedented, glare-free view of the rings and the fine dust that permeates them.

The rings were discovered in 1977, so this is the first opportunity astronomers have had to observe a Uranus ring crossing and perhaps to discover a new moon or two.

While the Keck II telescope and the Hubble Space Telescope have been looking at the planet for years in anticipation of this event, ground-based telescopes in Chile and southern California have joined them in targeting the planet during the actual ring crossing.

Based on the Keck observations, a team of astronomers led by Imke de Pater of University of California, Berkeley, reports today (Thursday, Aug. 23) in Science Express, the online edition of Science magazine, that the rings of micron-sized dust have changed significantly since the Voyager 2 spacecraft photographed the Uranus system 21 years ago. She will discuss the results during a talk today at the European Planetary Science Congress 2007 meeting in Potsdam, Germany.

The inner rings are much more prominent than expected, revealing material in otherwise empty regions of the system of rings.

“People tend to think of the rings as unchanging, but our observations show that not to be the case,” said de Pater, a UC Berkeley professor of astronomy. “There are a lot of forces acting on small dust grains, so it is not that crazy to find that the arrangement of rings has changed.”

Using the near infrared camera (NIRC2) and adaptive optics on the Keck II telescope on May 28, the team took striking images of the nearly edge-on ring appearing as a bright line bisecting a dim Uranus, which appears dark in the infrared. The observations were conducted during an engineering run by Marcos van Dam, adaptive optics scientist at the W. M. Keck Observatory, after the installation of a new wavefront sensor.

“The improvements to the adaptive optics systems allowed us to capture unbelievably crisp images of Uranus; it was as if the Keck telescope was orbiting in space,” said van Dam.

On Aug. 14, the Hubble Space Telescope also imaged the planet very near the moment when the rings were perfectly aligned with Earth, showing similar features but also including some recently-discovered outer rings. The image was released today by the Space Telescope Science Institute.

“The outermost ring is not visible in our infrared images,” said de Pater’s co-author, Heidi B. Hammel of the Space Science Institute in Boulder, Colo. “This ring is very blue, and therefore harder to see in the infrared. We may detect it when the rings are fully edge-on and when we can observe it for several hours.”

With further analysis of the Hubble data, astronomer Mark Showalter of the SETI Institute hopes to detect some of the small moons, and perhaps some not seen before, that shepherd the debris into distinct rings.

“Two little satellites called Cordelia and Ophelia straddle the brightest ring, the epsilon ring, and keep it in place, but people have always assumed there must be a bunch more of these satellites that are confining the nine other narrow rings,” Showalter said. “This is the unique viewing geometry that only comes along once in 42 years, when we have a chance of imaging these tiny satellites, because normally they are lost in the glare of the rings. Now, the rings are essentially invisible.”

Astronomers at the Very Large Telescope (VLT) in Chile, run by the European Southern Observatory (ESO), and at the Palomar Observatory in southern California operated by the California Institute of Technology, also observed Uranus during the current crossing.

“The VLT took data at the precise moment when the rings were edge-on to Earth,” said de Pater, who worked with two team members observing in Chile: Daphne Stam of the Technical University of Delft in the Netherlands and Markus Hartung of ESO. Meanwhile, astronomers Philip Nicholson of Cornell University in New York and Keith Matthews of Caltech observed from atop Mt. Palomar.

Until Voyager flew by in January 1986, the rings were only known from the way they temporarily blocked the light of stars passing behind Uranus. Earth-based images have been too blurry until recently, with the advent of Keck adaptive optics and the Advanced Camera for Surveys of the Hubble telescope. Nevertheless, when the sunlit side of Uranus’s rings are in full view of Earth, the densely-packed rings reflect so much light that their glare completely dominates the fainter glow from micron-sized dust.

Earth’s orbit around the sun permits three opportunities to view the rings edge-on: Uranus made its first ring crossing as seen from Earth on May 3, it made its second crossing on Aug. 16, and will cross for the third and last time on Feb 20, 2008. Though the last ring crossing relative to Earth will be hidden behind the sun, most of Earth’s premier telescopes, including Keck, Hubble, VLT and Palomar, plan to focus on the planet again in the days following Dec. 7.

“December 7 is the Uranian equinox, when the rings are perfectly edge-on to the sun, and after that, there is a brief period again when we will view the dark side of the rings, before they become illuminated again for another 42 years,” Hammel said.

The advantage of observations at a ring-plane crossing is that it becomes possible to look at the rings from the shadowed side. From that vantage, the normally-bright outer rings grow fainter because their centimeter- to meter-sized rocks obscure one another, while the dim inner rings get brighter as their material merges into a thin band along the line of sight.

The dust belts that Voyager saw differ radically from today’s dust distribution, according to coauthors de Pater and Showalter. Most interesting is a broad, inner ring called zeta, whose position today is several thousand kilometers farther from the planet than when it was discovered by Voyager.

“The ring may have moved, or it may be an entirely new ring,” noted Showalter.

Similar, dramatic changes in dust distribution have also been observed recently in Saturn’s and Neptune’s rings. This is not surprising, because gravity keeps the larger ring particles in orbit, but other smaller forces can nudge the tiny dust grains around, de Pater said. These forces include pressure from sunlight, drag produced as the dust plows through ionized plasma around Uranus, and even drag from the planet’s magnetic field.

“Impacts into the larger bodies in the system also could knock dust off and create new rings,” de Pater said.

“With further observations, the time scales over which these variations occur should provide new insight into the physical processes at work,” the authors concluded.

Support for the Keck observations came from the National Science Foundation, the National Aeronautics and Space Administration, the Keck Observatory and the UC Santa Cruz Technology Center for Adaptive Optics.

Press Release Courtesy of UC Berkeley

Polluted Dead Star Indicates Planets Like Earth May Have Formed Around Other Stars

Los Angeles (August 16th, 2007) The chemical fingerprint of a burned-out star indicates that Earth-like planets may not be rare in the universe and could give clues to what our solar system will look like when our sun dies and becomes a white dwarf star some five billion years from now.

Astronomers using data obtained at the W. M. Keck Observatory in Hawaii report a white dwarf star known as GD 362, which is surrounded by dusty rings similar to those of Saturn, has been contaminated by a large asteroid that left more than a dozen observable chemical elements in the white dwarf’s atmosphere. Such an observation is unprecedented in astronomy. Was there some kind of violent interaction between the star and the asteroid?

Astronomers from UCLA think that after about a billion years orbiting the white dwarf as part of an ancient planetary system, an asteroid got close enough to the star to be torn apart by its very strong gravitational force field. An Earth-sized but exceedingly dense white dwarf is the standard end state for most stars. This particular white dwarf, which is under investigation by the W.M. Keck Observatory in Hawaii, is located in the constellation Hercules, approximately 150 light-years, or 1,000 trillion miles, from Earth.

The asteroid broke apart into dust particles that orbited the white dwarf and over time “polluted the white dwarf’s atmosphere,” said Benjamin Zuckerman, UCLA professor of physics and astronomy and lead author of the research, which has been accepted for publication in an upcoming issue of the Astrophysical Journal, the premier journal of astronomy.

The astronomers note that the spectroscopic observations they are reporting constitute the first detailed assessment of the elemental composition of an object in an extrasolar planetary system.

“The relative abundance of the elements in the white dwarf’s atmosphere, polluted by the asteroid, appears similar to those in our Earth-Moon system,” Zuckerman said.

“What we have here is a composition of the white dwarf that is fairly similar to that of the inner planets of our solar system,” said Michael Jura, UCLA professor of physics and astronomy and co-author of the research. “Are there other terrestrial planets like Earth in other solar systems? This white dwarf’s fingerprint is a significant advance in demonstrating that something like terrestrial planet formation occurred around this other star and probably occurred around other stars as well, because it suggests the Earth’s composition is not unique.

“The asteroid that is being shredded is very iron-rich and abundant in calcium and other elements, and low in carbon, like a sturdy rock,” Jura added.

The research implies that the forces that made the Earth and our inner solar system seem to have occurred in this system as well, and probably around other white dwarfs too, Jura said.

Zuckerman said the research result does not rule out the possibility that two planets in this ancient planetary system collided and the orbiting dust and detected elements are from a piece of one of the colliding planets rather than from a more conventional asteroid.

“Something dramatic and violent probably happened,” he said.

What knocked the asteroid out of its original orbit? It probably was deflected by the gravitational field of a large planet, Zuckerman said.

Our own planetary system looks very stable, Zuckerman said, but billions of years from now, when the sun starts to expand in size and lose mass rapidly, the planets and asteroids will spiral away, and the planets closest to the sun, like Mercury and Venus, will be engulfed by the sun and destroyed.

“But other planets, probably including the Earth and the asteroid belt between Mars and Jupiter will spiral out, and their orbits then will make our stable system much less stable,” he said.

A third UCLA author on the paper, physics and astronomy associate professor Brad Hansen, said, “In our solar system, objects rich in iron formed closer to the sun than the objects rich in carbon and ice, which formed farther away, where it is colder. This research tells us about the origin of the asteroid, its temperature when it formed and its chemistry — conditions similar to the Earth’s.”

The group of astronomers, which also includes of UCLA graduate student Carl Melis and Detlev Koester at Germany’s University of Kiel, detected 17 elements in the atmosphere of the white dwarf that probably came from a large asteroid; the asteroid may have once been part of a larger body, perhaps like one of the inner planets of our solar system. Many of the elements have never before been detected in the atmosphere of a white dwarf, including the rare elements strontium and scandium.

The gravitational field of the white dwarf is so strong that all elements heavier than the lightest elements — hydrogen and helium — quickly sink into the white dwarf’s interior, Hansen said.

The asteroid likely broke up more than 100,000 years ago, and perhaps as long as a million years ago, the astronomers said. The star became a very hot white dwarf approximately 1 billion years ago and since then has been steadily cooling off.

Unlike GD 362, most white dwarfs are pristine in their composition.

“You wouldn’t notice another skyscraper in New York, but the same skyscraper in Nebraska would stick out like a sore thumb,” Hansen said. “That’s the case here. A little change in the atmosphere of a white dwarf is very obvious.”

The astronomers used the HIRES spectrometer on the Keck I Telescope to take optical spectra of the white dwarf, spanning the ultraviolet to the full visible range of light. Each element can be identified by its own characteristic spectrum.

The researchers said they find it quite remarkable that even at a distance of 1,000 trillion miles, the Keck HIRES measurements enable them to determine minute details of the bulk composition of a relatively tiny object — as astronomical sizes go — like an asteroid. Currently, no other known observational technique exists that allows for such compositional information to be obtained.

The remains of a white dwarf cool slowly over many billions of years as the dying ember makes its slow journey into oblivion. NASA funded the research.

Press Release Courtesy of UCLA

Keck Confirms Largest Exoplanet To Date

Mauna Kea (August 6th, 2007) An international team of astronomers has discovered the largest-radius and lowest-density exoplanet of all those whose mass and radius are known. It is a gas-giant planet about twice the size of Jupiter, and is likely to have a curved comet-like tail. It has been named TrES-4, as the fourth planet detected by the Trans-atlantic Exoplanet Survey (TrES) network of 10-cm telescopes.

TrES-4 is in the constellation Hercules and is the 20th transiting planet discovered so far. It orbits the star catalogued as GSC02620-00648, about 440 parsec (1435 light-years) away from Earth.

A transiting planet is a planet that passes directly in front of its host star as seen from Earth. When a transiting planet passes between its star and the Earth, the planet blocks some of the light from the star in a manner similar to that caused by the Moon’s passing between the Sun and Earth during a solar eclipse. In the case of TrES-4, this reduces the starlight by 1 percent, a tiny effect, yet detectable even with the small TrES telescopes.

The transiting planet also causes the star to undergo a small orbital motion, but measuring this effect (from which we can tell the mass of the planet) requires much larger telescopes, such as the Keck 10-m telescope in Hawaii, as was used in the case of TrES-4. Measuring the mass of the planet is a vital step in confirming that the transiting object is indeed a planet and not a star.

TrES-4 is noteworthy for having a radius 1.67 times Jupiter, and a mass only 0.84 times the mass of Jupiter, leading to the extremely low density of 0.222 g cm-3. As a comparison, Jupiter has a density of 1.3 g cm-3. The density of TrES-4 is so low that the planet would float on water.

“We continue to be surprised by how relatively large these giant planets can be.”, says Francis O’Donovan, a graduate student in astronomy at the California Institute of Technology who operates one of the TrES telescopes. “But if we can explain the sizes of these bloated planets in their harsh environments, it may help us better understand our own solar system planets and their formation.”

The study’s lead author, Georgi Mandushev from Lowell Observatory, noted the challenges such big planets present for theories of planet formation and evolution: “This find presents a new puzzle for astronomers who model the structure and atmospheres of giant planets. It highlights the diversity of physical properties among giant planets around other stars and indicates that we can expect more discoveries of unusual and enigmatic exoplanets in the near future.”

TrES is a global network of three small telescopes utilizing mostly amateur-astronomy components and off-the-shelf four-inch camera lenses: Sleuth telescope at Caltech’s Palomar Observatory in San Diego; Planet Search Survey Telescope (PSST) at Lowell Observatory; and STellar Astrophysics and Research on Exoplanets” (STARE) telescope in the Canary Islands.

Planet TrES-4 makes a complete revolution around its parent star every 3.55 days, so a year on this planet is shorter than a week on Earth. The planet is about 7 million kilometers away from its star - over ten times closer than is Mercury to the Sun - and so it is heated by the intense starlight to about 1600 degrees Kelvin, about 2300 degrees Fahrenheit.

In terms of mass and distance to its sun, TrES-4 is similar to HD209458b, and like this planet, it may have an extended outer atmosphere. Astronomers hypothesize that the outer atmospheric layers may be able to escape the planet’s gravity and form a curved comet-like tail.

To look for transits, the small telescopes are automated to take wide-field timed exposures of the clear skies on as many nights as possible. When an observing run is completed for a particular field-usually over an approximate two-month period - the data are run through software that corrects for various sources of distortion and noise.

The end result is a “light curve” for each of thousands of stars in the field. If the software detects regular variations in the light curve for an individual star, then the astronomers do additional work to see if the source of the variation is indeed a transiting planet. One possible alternative is that the object passing in front of the star is another star, fainter and smaller.

In order to accurately measure the size of the TrES-4 planet, astronomers used the 0.8-m telescope at the Lowell Observatory in Arizona, the 1.2-m telescope at the Whipple Observatory, also in Arizona, and the 10-m Keck telescope in Hawaii. The latter has proven to be essential for the confirmation of all four of the TrES planets.

Observations were carried out from September 2006 to April 2007.

The paper about the discovery of this extrasolar planet, “TrES-4: A Transiting Hot Jupiter of Very Low Density” has been submitted for publication by the Astrophysical Journal.

The paper’s authors are:
Georgi Mandushev and Edward Dunham of the Lowell Observatory (Flagstaff, AZ);
Francis O’Donovan and Lynne Hillenbrand of the California Institute of Technology (Pasadena, CA)
David Charbonneau (Alfred P. Sloan Research Fellow), Guillermo Torres, David W. Latham, Gáspár Bakos (Hubble Fellow), Alessandro Sozzetti, José Fernández and Guilbert Esquerdo of the Harvard-Smithsonian Center for Astrophysics (Cambridge, MA);
Mark Everett of the Planetary Science Institute (Tucson, AZ);
Timothy Brown of the Las Cumbres Observatory Global Telescope
Markus Rabus and Juan A. Belmonte of the Instituto de Astrofisica de Canarias in Tenerife, Spain;

This research is funded by NASA through the Origins of Solar Systems Program. The paper will be available online at http://arxiv.org/.

Press Release courtesy of California Institute of Technology

‘Blue Needle’ Presents New Challenge for Theorists

Mauna Kea (July 19th, 2007) Astronomers using the W. M. Keck Observatory and NASA’s Hubble Space Telescope to study disks of debris around stars have found one that is extremely lopsided.

While scientists are accustomed to finding asymmetrical accumulations of dust and larger bodies around stars, the debris disk around a star known as HD 15115 has a needle-like shape.

Astronomers believe the shape of debris disks can be affected by extrasolar planets or nearby stars on very elliptical orbits. Researchers are studying whether the gravity of a star known as HIP 12545, located about 10 light years from HD 15115, is the reason for the needle formation which appears blue when viewed in optical light with Hubble and near-infrared light with Keck.

While protoplanetary disks around young stars are thought to be the basis for the birth of planets, debris disks such as the one around HD 15115 are believed to be made up of the remnants of planet production. They are also similar to the Kuiper Belt, the region of our solar system extending from and beyond the orbit of Neptune that contains numerous objects made up of rock and ice. About 800 of those objects have been identified in recent years including a number of dwarf planets which the International Astronomical Union last year ruled also includes Pluto.

Astronomers believe debris disks, which are replenished by dust from collisions among its member objects, also can be affected by planets nearer to the star, much as Neptune ’s gravity can have an effect on Kuiper Belt objects. Paul Kalas, lead author of a study on HD 15115, cited one theory about planet-disk interaction closer to home as an example of how the needle formed. Some astronomers have developed a theory that Neptune originally formed between Saturn and Uranus, but was eventually kicked out to its present location beyond Uranus by a gravitational dance between Saturn and Jupiter before their orbits stabilized. “Therefore, we speculate that if such a planetary upheaval were occurring around HD 15115 at the present time, it could explain the highly asymmetric disk,” Kalas said.

The disk around HD 15115, which is the result of its highly elliptical orbit, is believed to begin at about the same distance from its star as the Kuiper Belt does from our Sun, but extends outward by at least ten times farther. The outer extend of the Blue Needle is detected to at least 550 AU making it the second-most extended debris disk seen to date.

Dusty disks are known to exist around at least 100 stars, but because of the difficulty in observing material close to the brightness of a star, less than a dozen have been studied closely. But the installation of the Advanced Camera for Surveys aboard the Hubble –before it malfunctioned early this year – led to increased discoveries of debris disks over the past three years. Kalas said while the Hubble has been used to survey debris disks in optical light, Keck has been invaluable for more detailed analysis in infrared wavelengths and to image the regions close to the star, where planet formation may have occurred.

From the evidence so far, Kalas considers both HD 15115 and HIP 12545 to be among nearly 30 stars that belong to the Beta Pictoris Moving Group. Moving groups are expanded clusters of stars believed to have a common birthplace and age, in this case about 12 million years, which are moving together loosely through space. HD 15115 has many similarities to another star know as AU Microscopii, a closely studied member of the Beta Pictoris Moving Group Located 32 light years form earth.

However, the debris disk around HD 15115 is not only far more asymmetrical than those observed around three other stars in the group, it also has significantly less dust than two of them of similar mass. Kalas said that the missing material might be related to the process that created the needle formation. “The missing mass is quite interesting,” he said. “Perhaps the mechanism which perturbed the disk into its current asymmetric morphology also shaved away a significant fraction of the mass.”

The dusty disk around HD 15115 was first indirectly detected in 2000 and first imaged using the Hubble Space Telescope in July 2006. The disk’s needle-like shape was extremely unusual, prompting the astronomers to request observations at W.M. Keck Observatory to confirm the disk’s existence and to image it closer to the star than was possible with Hubble. When the Keck near-infrared images were compared to the Hubble optical images, the disk was found to have an extremely blue color, which is also relatively rare among such disks. It was investigated further using Keck adaptive optics last year.

It is not yet known whether HIP 12545, the suspected gravitational perturber, has its own dusty disk. Kalas hopes to take advantage of Keck’s adaptive optics – which removes the distortions caused by the Earth’s atmosphere – to investigate that further this fall.

HD 15115 is classified as an “F” star, slightly larger than the Sun. HIP 12545 is an M star which has roughly half as much mass as the Sun.

As the discovery of Beta Pictoris a decade ago resulted in more than 300 scientific papers, Kalas believes that the research of HD 15115 will prompt a wealth of follow-up observations. Questions remaining to be answered include whether the needle formation is a temporary phenomenon. “The blue needle presents a host of new challenges for theorists,” Kalas said.

Funding for the project was provided by NASA. The research on HD 15115, has been accepted for publication in Astrophysical Journal Letters. The study was co-authored by James Graham, like Kalas an astronomer at the University of California at Berkeley and the Center for Adaptive Optics at the University of California at Santa Cruz , with graduate student Michael P. Fitzgerald.

The W. M. Keck Observatory (http://www.keckobservatory.org) is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California . In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

Astronomers Find Most Distant Known Galaxies

Pasadena, Calif. (July 10th, 2007) Using natural “gravitational lenses,” an international team of astronomers claim to have found the first traces of a population of the most distant galaxies yet seen-the light we see from them today left more than 13 billion years ago, when the universe was just 500 million years old.

Team leader Richard Ellis, the Steele Family Professor of Astronomy at the California Institute of Technology, will present images of these faint and distant objects in his talk on July 11 at the “From IRAS to Herschel and Planck” conference at the Geological Society in London. The meeting is being held to celebrate the 65th birthday of Royal Astronomical Society President Professor Michael Rowan-Robinson.

When light from very distant bodies passes through the gravitational field of much nearer massive objects, it bends in an effect known as “gravitational lensing.” In a pioneering technique, the Caltech-led group used massive clusters of galaxies-the best example of natural gravitational lenses-in a series of campaigns to locate progressively more distant systems that would not be detected in normal surveys. The team found the galaxies using the 10-meter Keck II telescope, sited atop Mauna Kea on the Big Island of Hawaii.

Ellis explains, “Gravitational lensing is the magnification of distant sources by foreground structures. By looking through carefully selected clusters, we have located six star-forming galaxies seen at unprecedented distances, corresponding to a time when the universe was only 500 million years old, or less than four percent of its present age.”

It is thought that when the universe was 300,000 years old it entered a period when no stars were shining. Cosmologists refer to this phase of cosmic history as the “Dark Ages.” Pinpointing the moment of “cosmic dawn” when the first stars and galaxies began to shine and the Dark Ages ended is a major observational quest and provides the motivation for building future powerful telescopes such as the Caltech’s Thirty Meter Telescope, and the space-borne James Webb Telescope.

The new survey is the culmination of three years’ painstaking observations which represent the thesis of Caltech graduate student Dan Stark. “Using Keck II, we have detected six faint star-forming galaxies whose signal has been boosted about 20 times by the magnifying effect of a foreground cluster. That we should find so many distant galaxies in our small survey area suggests they are very numerous indeed. We estimate the combined radiation output of this population could be sufficient to break apart (ionize) the hydrogen atoms in space at that time, thereby ending the Dark Ages,” said Stark.

Proving definitively that each of the six objects is unambiguously at these enormous distances (and hence being viewed at such early times) is hard, even with the most powerful instruments. “As with all work at the frontiers, skeptics may wish to see further proof that the objects we are detecting with Keck are really so distant,” confessed Ellis. However, in addition to numerous checks the team has made (described in their published scientific article) following their initial discovery a year ago, Ellis and Stark point to supporting evidence from galaxies containing old stars that are seen when the universe was just a bit older.

“We can infer the universe had a lot of star formation at these early times from Spitzer Space Telescope measurements of larger galaxies seen when the universe was about 300 to 500 million years older,” explains Stark. “These galaxies show the tell-tale sign of old stars (and were described in earlier work by Ellis and Stark with UK scientist Andrew Bunker). To produce these old stars requires significant earlier activity, most likely in the fainter star-forming galaxies we have now seen.”

Also associated with the program is Caltech postdoctoral scholar Johan Richard, who is leading a similar, but independent, survey of magnified galaxies detected with the Hubble and Spitzer space telescopes. Although that work is not yet complete, preliminary findings support the conclusions of the Keck II survey. European collaborators include Jean-Paul Kneib of the Laboratory of Astrophysics at Marseilles, and Graham Smith at the University of Birmingham.

Press Release Courtesy of California Institute of Technology

Science Paper available in the Astrophysical Journal, Volume 663, pages 10-28, 2007

Dr. Ellis explains the search for Cosmic Dawn during a public talk:
MP3 file (22MB file); slides posted here (8 MB file)

Astronomers Measure Mass of Largest Dwarf Planet

Baltimore (June 14th, 2007) W. M. Keck Observatory and NASA’s Hubble Space Telescope have teamed up to precisely measure the mass of Eris, the largest member of a new class of dwarf planets in our solar system. Eris has 27 percent more mass than Pluto, formerly the largest member of the Kuiper Belt of icy objects beyond Neptune.

Hubble observations in 2006 showed that Eris is slightly physically larger than Pluto. But the mass could only be calculated by observing the orbital motion of the moon Dysnomia around Eris. Multiple images of Dysnomia’s movement along its orbit were taken by Hubble and Keck.

Astronomer Mike Brown of the California Institute of Technology in Pasadena, Calif. and colleagues also report in this week’s Science Magazine that Dysnomia is in a nearly circular 16-day orbit. This favors the idea that Dysnomia was born out of a collision between Eris and another Kuiper Belt object (KBO). A gravitationally captured object would be expected to be in a more elliptical orbit.

The satellites of Pluto, as well as the Earth-Moon system are also believed to have been born out of a collision process where debris from the smashup goes into orbit and coalesces into a satellite.

By comparing the mass and diameter, Brown has calculated a density for Eris of 2.3 grams per cubic centimeter. This is very similar to the density of Pluto, the large Kuiper Belt object 2003 EL61, and Neptune’s moon Triton which is likely a captured KBO. These higher densities imply that these bodies are not pure ice but must have a significant rocky composition.

The discovery of Eris in 2005 (originally nicknamed Xena, and officially cataloged 2003 UB313) prompted a debate over the planetary status of Pluto because astronomers realized they would have to call it the “10th” planet if Pluto retained its own planetary status, which was already under debate. This led the International Astronomical Union, in 2006, to make a new class of solar system object called dwarf planets. These are spherical bodies in hydrostatic equilibrium (objects that have sufficient gravity to overcome their own rigidity and form a spherical shape) like the planets, but unlike the major planets in the solar system, they have not gravitationally cleared out the neighborhood of particles and small debris along their orbits.

Press release courtesy of Hubble Space Telescope

‘OLYMPIAN GALAXY’ NEAR ANDROMEDA GIVES CLUES TO HOW GALAXIES FORM

Honolulu (May 28th, 2007) A newly discovered dwarf galaxy in the Local Group has been found to have formed in a region of space far from our own and is falling into our system for the first time in its history, according to new data obtained at the W. M. Keck Observatory. An international team of astronomers report that the dwarf galaxy, Andromeda XII, marks the best piece of evidence for small galaxies which are just now arriving in our Local Group. The finding provides an important test for simulations of galaxy formation.

Dwarf galaxies and streams of stellar material mark the visible remnants of galactic merging events from which large galaxies are made. Cosmology models predict small galaxies form along a web of filamentary structures in the universe, and then gradually fall into dense groups and cluster environments. Small galaxies should still be falling into the Local Group, yet none have been found—until now.

“Other Local Group dwarf galaxies are thought to have extreme orbits, including Leo I, Andromeda XIV and Andromeda XI, but Andromeda XII really stands out as a contender for a new entrant into the Local Group,” said the lead author of the study, Dr. Scott C. Chapman of the University of Cambridge, Institute of Astronomy. “The others have likely already been seriously harassed by Andromeda and the Milky Way.”

Nicknamed the ‘Olympian Galaxy’ after the Twelve Olympians in the Greek Pantheon, Andromeda XII was first discovered in October 2006 during a wide-field survey taken with the Canada-France Hawaii Telescope’s “MegaCam” instrument. It is the faintest dwarf galaxy ever discovered near to Andromeda (M31), and may have the lowest mass ever measured. Dwarf galaxies are the smallest stellar systems showing evidence for a substantial amount of dark matter.

Dr. Chapman’s observations confirmed Andromeda XII is distinct from all other satellite galaxies in the Local Group. It is a fast-moving galaxy on a highly eccentric orbit, located at a great distance from the center of M31, about 115 kiloparsecs (375,000 light years). Importantly, Andromeda XII lies significantly behind M31 as viewed from the Milky Way, almost certainly falling in for the first time. Because Andromeda XII has lived its life in a very different environment than the Local Group, it gives astronomers a pristine object for studying star formation histories, dark matter distribution, and other parameters that would be influenced by the Local Group gravity that has affected all the in other dwarf galaxies.

“Andromeda XII may be the first galaxy of the local group ever observed that has not yet been disrupted by the strong gravity of the Local Group,” said Dr. Jorge Penarrubia of the University of Victoria, a co-author of the study.

The DEIMOS spectrograph at Keck II, one of two 10-meter telescopes the W. M. Keck Observatory operates on the summit of Mauna Kea, was key in making the discovery. It was used to observe 49 stars in the region of Andromeda XII, and confirmed that eight were members of the new dwarf galaxy. Follow-up observations were also conducted at the Green Bank Telescope in West Virginia to measure the amount of interstellar gas in the galaxy, and the Subaru telescope in Hawaii helped determine a more precise distance.

“Without the spectra we obtained with DEIMOS, it would have been impossible to make any useful claims about the orbit of Andromeda XII, its evolution, its speed or its dark matter content,” added Dr. Chapman.

Andromeda XII is falling very quickly through the Local Group from behind Andromeda, the only one of Andromeda’s satellites which exceeds the apparent escape velocity for Andromeda. It is possible that Andromeda XII may be just a short-term visitor. It is such a low-mass galaxy that it may not slow down much as it passes through the Local Group.

“It is a pleasure to see the speed of this new, fascinating member of the Local Group clocked using Keck II and DEIMOS,” added W. M. Keck Observatory Director Taft Armandroff. “The powerful combination of Keck and DEIMOS has added many contributions to our understanding of Local Group galaxies.”

The age of the Universe is not old enough for Andromeda XII to have started in the dense Local Group and be on its second trip through our system. Andromeda XII probably formed in a dense filament structure, toward the general direction of the M81 group. However, the distance is about three times too large for it to have actually come from the M81 group. A likely scenario is Andromeda XII formed in a filamentary region of space that connects the Local Group to the M81 group.

“The high speed of Andromeda XII really surprised me; I wasn’t expecting to see any of our newly discovered dwarfs moving so fast. We will likely have to revise our mass estimates of Andromeda upward as a result.” added Rodrigo Ibata.

A paper reporting the discovery, “Strangers in the Night: The discovery of a Dwarf Spheroidal Galaxy on its First Local Group Infall,” will appear in an upcoming issue of the Astrophysical Journal. Funding was provided by a fellowship from the Canadian Space Agency and the Natural Sciences and Engineering Research Council of Canada. Additional support was provided by Adrian Jenkins who provided use of important computer simulations.

The study was co-authored by Jorge Penarrubia, Alan McConnachie, Aaron Ludlow of the University of Victoria; Rodrigo Ibata, Observatoire de Strasbourg; Nicolas F. Martin, Max-Planck Institut fur Astronomie; Andrew Blain and Bruno LeTarte, California Institute of Technology; Michael Irwin, University of Cambridge Institute of Astronomy; Geraint Lewis, University of Sydney Institute of Astronomy; Fred Lo and Karen O’Neil, NRAO Green Bank Telescope.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

More images on the team Web site at: http://www.ast.cam.ac.uk/~schapman/and12.html

Related media
Link to movie showing simulution of late accreting satellites (coloured circles) into an environment similar to our Local Group, from Ludlow et al. (2007) (gif)

Adaptive optics pinpoints two supermassive black holes in colliding galaxies

Santa Cruz (May 17th, 2007) Astronomers have used powerful adaptive optics technology at the W. M. Keck Observatory in Hawaii to reveal the precise locations and environments of a pair of supermassive black holes at the center of an ongoing collision between two galaxies 300 million light-years away.

The new observations of the galaxy merger known as NGC 6240 reveal that each of the black holes resides at the center of a rotating disk of stars and is surrounded by a cloud of young star clusters formed in the merger, said Claire Max, professor of astronomy and astrophysics at the University of California, Santa Cruz.

“People had observed this pair of colliding galaxies at different wavelengths and seen what they thought were the black holes, but it’s been very hard to make sense of how the observations at various wavelengths correspond to each other,” Max said. “The adaptive optics results enabled us to tie it all together, so now we can really see it all—the hot dust in the infrared, the stars in the visible and infrared, and the x-rays and radio emissions coming from right around the black holes.”

Adaptive optics (AO) enables astronomers to counteract the blurring effects of turbulence in Earth’s atmosphere, which degrades images seen by ground-based telescopes. Max, who directs the Center for Adaptive Optics at UC Santa Cruz, is the lead author of a paper describing the new findings published by the journal Science (Science Express online, May 17, and in a later print edition). Her coauthors are Gabriela Canalizo, who worked with Max as a postdoctoral researcher at Lawrence Livermore National Laboratory (LLNL) and is now at UC Riverside, and Willem de Vries, a physicist with LLNL and UC Davis.

Images of NGC 6240 in visible light from the Hubble Space Telescope show the outer parts of the colliding galaxies distorted by their ongoing merger into long tidal tails of stars, gas, and dust. In the bright central region, two distinct nuclei can be discerned, but clouds of dust obscure much of the visible light from the core. The presence of two supermassive black holes in NGC 6240 was first demonstrated by x-ray observations from NASA’s Chandra X-ray Observatory in 2002. Two pointlike radio sources were also detected in the central region.

But trying to match up the data from one instrument with those obtained at different wavelengths by other instruments is very difficult because there are few common reference points in the various wavelength regimes, Max said. The infrared images her group obtained using the AO system on the 10-meter Keck II Telescope provided the high spatial resolution needed to identify features in NGC 6240 that can be seen in different wavelengths.

“With the infrared images we got at Keck, we were able to line up the information from all the different wavelengths to determine which features in the images are the black holes,” Max said.

The infrared wavelengths are less affected by dust than visible light, and the Keck infrared images show distinct nuclei with complex substructure surrounded by many faint point sources. The faint point sources are young star clusters produced in a burst of star formation triggered by the collision of the two gas-rich galaxies. Pinpointing which of the features in the infrared images correspond to the positions of the black holes involved several steps and required Keck adaptive optics observations at different infrared wavelengths.

“We uncovered it piece by piece, until we were able to make the correspondence between the black holes and the features seen at different wavelengths, as well as the stuff around them,” Max said. “It really shows how powerful the Keck adaptive optics system is. We were also fortunate to have an extraordinarily good observing night.”

Galaxy mergers are thought to play a major role in the evolution of galaxies and may help explain many of their properties. For example, astronomers have found that the mass of the black hole at the center of a galaxy is highly correlated with large-scale properties of the galaxy itself. The “coevolution” hypothesis explains this correlation as the result of both the black hole and the galaxy around it growing incrementally in repeated merger events over cosmic timescales.

“The gravitational influence of the black hole is actually limited to a relatively small region right around it, so how can it affect the rest of the galaxy? But if the black hole and the galaxy around it evolved together through the same sequence of merger events, that would explain the correlations,” Max said. “That’s why people are so excited about understanding galaxy mergers, and here we’re seeing it in action.”

The two black holes in NGC 6240 will eventually, in 10 million to 100 million years, spiral into each other and merge, producing a powerful burst of gravitational radiation, she said.

This research was supported in part by Lawrence Livermore National Laboratory under the auspices of the U.S. Department of Energy and by the Center for Adaptive Optics, a National Science Foundation Science and Technology Center managed by UC Santa Cruz. The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA.

Press Release Courtesy of UC Santa Cruz: http://www.ucsc.edu

Brightest Supernova Ever Seen

Berkeley (May 7th, 2007) An exploding star first observed last September is the largest and most luminous supernova ever seen, according to University of California, Berkeley, astronomers, and may be the first example of a type of massive exploding star rare today but probably common in the very early universe.

Unlike typical supernovas that reach a peak brightness in days to a few weeks and then dim into obscurity a few months later, SN2006gy took 70 days to reach full brightness and stayed brighter than any previously observed supernova for more than three months. Nearly eight months later, it still is as bright as a typical supernova at its peak, outshining its host galaxy 240 million light years away.

UC Berkeley post-doctoral fellows Nathan Smith and David Pooley estimate the star’s mass at between 100 and 200 times that of the sun. Such massive stars are so rare that galaxies like our own Milky Way may contain only a dozen out of a stellar population of 400 billion.

“This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” said Smith, who led a team of astronomers from UC Berkeley and the University of Texas. “That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We’ve never seen that before.”

“Of all exploding stars ever observed, this was the king,” said Alex Filippenko, UC Berkeley astronomer and leader of the ground-based observations at the University of California’s Lick Observatory in California and the W. M. Keck Observatory in Hawaii. “We were astonished to see how bright it got, and how long it lasted.”

Based on the Lick and Keck observations, plus data from the Chandra X-ray Observatory, Smith, Pooley, Filippenko and their colleagues argue that the stellar explosion was not your run-of-the-mill supernova, but a possible pair-instability supernova.

Stars with masses at least 10 times greater than our sun end their lives after burning hydrogen to helium, helium to carbon, and on to larger elements until they reach iron, when fusion stops. Toward the end of this process, the heat produced in the core of the star becomes insufficient to support the outer layers, which collapse inward, finishing the fusion process and crunching the core to a neutron star or black hole. The outer layers of the star are blown off in a bright flare-up we observe as a supernova.

For stars much more massive than this, ranging from 140 solar masses to as many as 250, the temperature at the core becomes so great that before the fusion cascade is complete, high-energy gamma rays in the core start annihilating one another, creating matter-antimatter pairs, mostly electron-positron pairs. Since gamma radiation is the energy that prevents collapse of the outer layers of the star, once the radiation starts disappearing, the outer layers fall inward. The net result is a thermonuclear explosion that, theoretically, would be brighter than any typical supernova. In this type of supernova, the star is blown to smithereens, leaving behind no black hole.

“This discovery forces us to go back to the drawing board to understand how the most massive stars die,” Smith said. “Instead of just winking away into a black hole, they apparently can suffer these brilliant explosions that can be seen far across the universe. The fact that this thing is so bright, and stayed bright for a long time, makes our chances of detecting them in the early universe much better.”

Such pair-instability supernovas should theoretically produce a greater percentage of heavy elements. According to Smith, the radioactive decay of
nickel-56 produces most of the light of a supernova, and this pair-instability supernova produced about 20 solar masses of nickel, compared to maybe 0.6 solar masses in a Type Ia supernova. Astronomers think that a large proportion of the universe’s first stars were supermassive stars like this that, upon exploding, seeded the early universe with the heavy elements from which planets and later, humans, were made.

“We may have witnessed a modern-day version of how the first generation of the most massive stars ended their lives, when the universe was very young,” Filippenko said.

The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding, reminiscent of the star eta Carinae, a so-called luminous blue variable which, at 100 to 120 solar masses, is the most massive star in our galaxy.

“This is also very exciting because it suggests that eta Carinae, only 7,500 light years away, might possibly explode in a similar manner, becoming a spectacularly bright star in our sky,” Filippenko said.

“We don’t know for sure if Eta Carinae will explode soon, but we had better keep a close eye on it just in case,” added Mario Livio of the Space Telescope Science Institute in Baltimore, Md., who was not involved in the research. “Eta Carinae’s explosion could be the best star-show in the history of modern civilization.”

University of Texas graduate student Robert Quimby first observed the supernova on Sept. 18, 2006 in the galaxy NGC 1260, located in the constellation Perseus. Filippenko’s team immediately began observing it with its dedicated supernova search and monitor telescope at Lick, the Katzman Automatic Imaging Telescope.

Filippenko and his graduate student Ryan Foley subsequently obtained spectra of the star using the Lick 3-meter Shane telescope and the DEIMOS spectrograph mounted on the Keck II telescope.

Pooley led the Chandra observation, which allowed the team to rule out the most likely alternative explanation for the supernova, namely that it was an explosion of a white dwarf star into a dense, hydrogen-rich environment.

“If that were the case, this supernova would have been 1,000 times brighter in X-rays than what we detected with Chandra,” said Pooley. “This must have been an extremely massive star.”

“In terms of the effect on the early universe, there’s a huge difference between these two possibilities,” said Smith. “One pollutes the galaxy with large quantities of newly synthesized elements, and the other locks them up forever in a black hole.”

“One exciting repercussion of this is that, if pair-instability supernovas really are this bright, it gives us hope that the James Webb Space Telescope might actually be able to detect these explosions from the first stars, thereby verifying that they may actually exist,” he added.

The results from Smith, Pooley, Filippenko and their colleagues, including Weidong Li, Ryan Chornock, Jeffrey M. Silverman, Joshua S. Bloom and Charles Hansen of UC Berkeley and J. Craig Wheeler of the University of Texas, will appear in The Astrophysical Journal.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate. The work also was supported by the National Science Foundation and the W. M. Keck Foundation.

Press Release Courtesy of UC Berkeley

SN 2006gy: Discovery of the most luminous supernova ever recorded, powered by the death of an extremely massive star like Eta Carinae

“Red Square” Captured by Palomar and Keck Telescopes

Pasadena (April 11th, 2007) Astronomers announced the arrival of a new member in the pantheon of exotically beautiful celestial objects. Christened the “Red Square” by Peter Tuthill, leader of the team, the image was compiled with data from the 200-inch Hale Telescope at Palomar Observatory, owned and operated by the California Institute of Technology, and the Keck II telescope atop Mauna Kea, Hawaii.

The findings appear in the April 13 2007 edition of the journal Science in an article titled “A symmetric bipolar nebula around MWC 922,” written by Tuthill from the University of Sydney and coauthor James Lloyd of Cornell University.”

Discoveries as beautiful—and interesting—as this one don’t come around very often in astronomy,” said Tuthill, “and it took some of the world’s most advanced telescopes, together with a good dose of luck, to find this jewel hidden among the myriad stars in the galaxy.”

“The key to finding it was in the revolutionary new imaging technology of adaptive optics, which acts like a myopia cure for a telescope,” agreed Lloyd. “Startlingly clear images capable of revealing objects like this are now possible without the blurring.”

The pair were studying a hot star called MWC 922 in the constellation Serpens (the serpent mythologically associated with the origin of medicine). The image shown here combines data taken in near-infrared light (1.6 microns) and shows a region 30.8 arcseconds on a side around MWC 922. As the outer periphery of the nebula is very faint compared to the core, the image has been processed and sharpened to display the full panoply of detail and structure.

“The thing that really takes your breath away is the astonishing degree of symmetry within the intricate linear forms,” said Tuthill. “If you fold things across the principle diagonal axis, you get an almost perfect reflection symmetry. This makes the Red Square nebula the most symmetrical object of comparable complexity ever imaged.”

The overall architecture of twin opposed conical cavities (commonly known in astronomy as a “bipolar nebula”) is seen to be adorned with a remarkable sequence of sharply defined linear rungs or bars. This series of rungs and conical surfaces lie nested, one within the next, down to the heart of the system, where the hyperbolic bicone surfaces are crossed by a dark lane running across the principle axis.

One particularly fascinating feature visible in the images is a series of faint radial spokes, like teeth of a comb, pointing away from the center.

“Structures such as this are rarely seen in nebulae, and the high degree of regularity in this case may point to the intriguing possibility that these bands are shadows cast by periodic ripples or waves on the surface of an inner disk close to the star at the heart of the system,” said Lloyd.

But the most compelling and important implication for astronomy comes from the three-dimensional structure implied by the Red Square images.

“If you can really get a mental grasp of the three-dimensional geometry implied by the Red Square images,” said Tuthill, “then it is fascinating to take a second look at one of the most famous astronomical images of them all: SN1987A.” An image of the supernova as seen by the Hubble Space Telescope is to the right, showing the beautiful and unexpected ring system revealed around SN1987A—the only naked-eye supernova since the discovery of the telescope.

“We are not saying that the star MWC 922 at the heart of the Red Square is about to explode as a supernova,” said Lloyd, “but we’re not ruling it out either, and if it did it would certainly put on quite a show as it kindles the outer eaches of its nebula.”

Whatever the fate of the central star, the remarkable series of bars seen in the Red Square make it the best astrophysical laboratory yet discovered for studying the physics of generating the mysterious sharp polar-ring systems like that around SN1987A.

According to Tuthill, “This is just the beginning-a system as complex and fascinating as this is bound to keep us guessing for years to come.“The image was made possible by the Palomar Adaptive Optics System, built by Caltech Optical Observatories and Jet Propulsion Laboratory, and captured by its companion infrared camera, built by Cornell University.

Press release provided by California Insitute of Technology.

Fundamental Property of Galaxies Discovered at W. M. Keck Observatory

Kamuela (March 6th, 2007) A new study using data collected by the W. M. Keck Observatory in Hawaii has revealed that certain fundamental properties of galaxies have actually changed very little over the last 8 billion years, nearly half of the age of the universe.

According to the research, the relationship between a galaxy’s mass and a new speed indicator that measures movement of its stars and gas remains the same for all forms of galaxies, from spirals like our own Milky Way, to elliptical galaxies, and even the so-called “train wrecks” left over by galactic mergers.

“Surprisingly, if you use this new speed indicator to measure the motions of stars and gas in a galaxy, you can predict the mass in stars the galaxy has with pretty high accuracy,” said Susan Kassin, a post-doctoral researcher at the University of California, Santa Cruz and lead author of the study.

Galaxies like our Milky Way are made up of billions of stars formed into a spiral disk along with some gas. Like a spinning pinwheel, our galaxy also spins, but at a speed of a few hundred kilometers per second.

It’s known that half of the age of the universe ago, many galaxies look more disheveled, as they are assembled through galaxy collisions and accretion of new gas and stars. According to the research, disheveled galaxies and the remnants of galaxy collisions have mixed-up velocities in addition to some orderly rotation. Furthermore, the research found that when all these velocities are totaled up, the total amount of motion was found to be similar to that of more well behaved galaxies. “This suggests that the mixed-up velocities may settle down to orderly rotation over time as the universe ages,” said Ben Weiner, a researcher at Steward Observatory at the University of Arizona and a co-author of the study.

There are three main types of galaxies in the universe: spiral or disk-like galaxies like our own Milky Way, elliptical or cloud-like galaxies, and the remnants of galaxy collisions. It was previously known that when it comes to spiral galaxies, the more massive the galaxy, the faster its stars and gas rotate. The relation between the mass in stars of spiral galaxies and the rotation speed of their stars and gas is known as the Tully-Fisher relation. When it comes to elliptical galaxies, the more massive a galaxy is, the faster the random motions of its stars. This relation is known as the Faber-Jackson relation. The latest research went a step further; discovering a new relation between how massive a galaxy is and a new speed indicator that takes into account both rotation velocity and random or disordered motion. This new relation applies to spiral, elliptical, and other types of galaxies, like disheveled galaxies or the remnants of galaxy collisions, and has remained essentially the same over the past 8 billion years – roughly half the age of the universe.

Kassin, Weiner, and the other researchers were able to bring together both the Tully-Fisher and Faber-Jackson relations – and include “disturbed” or train-wreck galaxies which previously didn’t figure in either – by using a new speed indicator, a number which when applied to galaxies, allows astronomers to better mathematically define the movement of stars.

“This relation holds for all the galaxies, no matter what they look like,” Kassin said. “It ties together the Faber-Jackson relation with the Tully-Fisher relation and works for all kinds of odd-ball galaxies that are more common in the early universe.”

According to Sandra Faber, co-author of the study and one of the namesakes of the Faber-Jackson relation which she helped develop in 1976, the research is believed to reflect a fundamental property of the universe.

“Both of these relations were imprinted by the nature of fluctuations that made galaxies in the first place,” she said.

The recent study involved 544 distant galaxies of various types, which according to Kassin makes this the largest study to date of the speed and movement of distant galaxies’ stars and other matter. The galaxies studied ranged in redshift from 0.1 to 1.2, which means their light was emitted between 2 billion and 8 billion years ago. Redshift is a way of gauging the distance of an object by measuring how much of the wavelength of its light has shifted toward the redder regions of the spectrum due to galaxies moving away from us because of the expansion of the universe. It is similar to the Doppler Effect which involves changes in sound from an object moving away from oneself.

Kassin said the DEIMOS spectrograph at Keck II, one of two 10-meter telescopes the observatory operates on the summit of Mauna Kea, was key to obtaining the amount of data necessary for the study. “Without it, we wouldn’t have been able to have anything close to this large of a sample,” she said. Additional data came from the Hubble Space Telescope and the Canada-France-Hawaii Telescope, which is also located atop Mauna Kea. The results of the research have been presented in a study to be published in a special issue of “Astrophysical Journal Letters” devoted to the initial results of a far-reaching study of galaxies know as AEGIS, for All-wavelength Extended Groth Strip International Survey. AEGIS involves nearly 100 scientists from 16 institutions in Europe, North America, and Asia studying a certain area of the sky using a variety of wavelengths ranging from X-rays to radio and including ultraviolet and visible light. For more information see the Web site at: The Web site is located at http://aegis.ucolick.org.

Funding for this research was provided by the National Science Foundation and NASA. The study was also co-authored by David Koo, Justin Harker, Anne Metevier, Andrew Phillips, Jürg Diemand, Nicholas Konidaris, Kai Noeske and of UCSC; Jennifer Lotz of the National Optical Astronomical Observatories; Kevin Bundy of the University of Toronto; Michael Cooper and Darren Croton of the University of California at Berkeley and Christopher Willmer of Steward Observatory at the University of Arizona.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

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‘Comet Galaxy’ Ripped Apart by Galaxy Cluster

Garching, Germany (March 2nd, 2007) The NASA/ESA Hubble Space Telescope, in collaboration with several other ground- and space-based telescopes including Keck, has captured a galaxy being ripped apart by a galaxy cluster’s gravitational field and harsh environment.

The finding sheds light on the mysterious process by which gas-rich spiral-shaped galaxies might evolve into gas-poor irregular- or elliptical-shaped galaxies over billions of years.

The new observations also show one mechanism to form the millions of “homeless” stars seen scattered throughout galaxy clusters.

There are many galaxies of different shapes and sizes around us today. Roughly half are gas-poor elliptical-shaped galaxies with little new star formation activity, and half are gas-rich spiral and irregular galaxies with high star formation activity. Observations have shown that gas-poor galaxies are most often found near the centre of crowded galaxy clusters, whereas spirals spend most of their lifetime in solitude.

The mystery, gleaned from deep observations of the universe, is that when the universe was half its present age only one in five galaxies was a gas-poor galaxy. So, where do all of today’s gas-poor galaxies come from?

Scientists suspect that some kind of transforming process must have taken place, but because galaxy evolution occurs over billions of years, scientists have so far not been able to see the transformation at work.

New observations with Hubble by an international team led by Luca Cortese of Cardiff University, United Kingdom, provide one of the best examples to date of this metamorphosis. While looking at the galaxy cluster Abell 2667, astronomers found an odd-looking spiral galaxy that ploughs through the cluster after being accelerated to at least 3.5 million km/h by the enormous combined gravity of the cluster’s dark matter, hot gas and hundreds of galaxies.

“By combining Hubble observations with various ground- and space-based telescopes, we have been able to shed some light on the evolutionary history of galaxies,” said Cortese.

As the galaxy speeds through, its gas and stars are being stripped away by the tidal forces exerted by the cluster–-just as the tidal forces exerted by the moon and Sun push and pull the Earth’s oceans. Also contributing to this destructive process is the pressure of the cluster’s hot gas plasma reaching temperatures as high as 10-100 million degrees.
Both processes – the tidal forces and the aptly named “ram pressure stripping” resulting from the action of the hot cluster gas – resemble those affecting comets in our Solar System.

For this reason, scientists have nicknamed this peculiar spiral with its tail the “Comet Galaxy”.

“This unique galaxy, situated 3.2 billion light-years from Earth, has an extended stream of bright blue knots and diffuse wisps of young stars driven away by the tidal forces and the ‘ram pressure stripping’ of the hot dense gas,” said Jean-Paul Kneib, a study collaborator from the Laboratoire d’Astrophysique de Marseille.

“Millions of now homeless stars have been snatched away from their mother galaxy, which will lead the galaxy to age prematurely,” said co-investigator Giovanni Covone of Osservatorio Astronomico di Capodimonte.

Even though its mass is slightly larger than that of the Milky Way, the spiral will inevitably lose all its gas and dust as well as its chance of generating new stars later, and become a gas-poor galaxy with an old population of red stars.

“However, in the midst of all this destruction, the cluster’s strong forces have triggered a baby-boom of star formation,” adds Covone.

Scientists estimate that the total duration of the transformation process is close to one billion years. What is seen now in the Hubble image is roughly 200 million years into the process.

The strong gravitational pull exerted by the galaxy cluster’s collective mass has bent the light of other, more distant galaxies and distorted their shapes-–an effect called gravitational lensing. The giant bright banana-shaped arc seen just to the left of the cluster centre corresponds to the magnified and distorted image of a distant galaxy that lies behind the cluster’s core.

At the cluster’s centre another rare feature can be seen: the vivid blue light from millions of stars created in a so-called cooling flow. Some of the hot cluster gas is cooling in a filamentary structure as it falls into the cluster’s core, setting off the birth of lots of bright blue stars outshining their environment. This may be the clearest picture of this phenomenon yet.
The Hubble image was taken by Hubble’s Wide Field and Planetary Camera 2 in October 2001 and is a composite of three observations through a blue filter (F450W, 12,000 seconds), a green filter (F606W, 4,000 seconds) and a near-infrared filter (F814W, 4,000 seconds). ESO’s Very Large Telescope and the twin Keck Telescopes in Hawaii were used for optical spectroscopy and near-infrared photometry, which helped determine the age of the star-forming region. NASA’s Spitzer Space Telescope and Chandra X-Ray Observatory were used jointly to confirm that the activity in the “Comet Galaxy” was due to vigorous star-formation and not a super-massive black hole.

Press release courtesy of Hubble European Space Agency

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Earthquake Update from W. M. Keck Observatory

Kamuela (February 28th, 2007) The Observatory has returned to standard operating procedures after a 6.7-magnitude earthquake struck off the west coast of Hawaii October 15, 2006. The earthquake was the largest to hit Hawaii in 20 years. There were no injuries at W. M. Keck Observatory and no damage to the mirrors or optical systems of the twin Keck telescopes.

During the six-week earthquake recovery process the Observatory modified work schedules and implemented new planning processes in order to return the facility to science operations as quickly as possible. The result was quick return to science, with limited operations taking place as early as Oct. 24th, a mere nine days following the first earthquake.

Both telescopes are now collecting science data, though at temporarily reduced slew speeds and some minor performance restrictions. The Observatory continues to evaluate the performance of both telescopes in comparison to pre-earthquake levels and original specifications.

“We are extremely appreciative and thankful for the tremendous hard work, dedication and professionalism shown over the past several months,” remarked Keck Observatory Director Dr. Taft Armandroff. “We have juggled many parallel activities during the earthquake repair process and have helped our observers collect as much valuable science as possible.
The most important accomplishment is that we have been able to conduct these recovery efforts safely.”

The Hualalai Lecture Theater has been repaired and has been restored to operation.

Sarah Anderson
Electronic Technicians Robert Novak (left) and Gary Anderson (right) repair the Keck II telescope drive and control system. Anderson’s arm is reflected in the oil surface of the hydraulic bearing on which the telescope moves.

Credit: Sarah Anderson
Drew Medeiros (left) Chris Hunt (right) and Jim Bell (bottom) adjust the Keck I dome restraints to return the wheels to proper position.

Credit: Sarah Anderson
The historic Keck II remote operations control room in Kamuela, Hawaii following a 6.7 magnitude earthquake and a series of strong aftershocks.

Credit: Sarah Anderson
Summit crew move the Keck I telescope by hand during recovery efforts.

Large Survey Identifies Young Binaries To Test Models Of Star Formation

Seattle (January 10th, 2007) Results from the largest survey of its kind conducted at the W. M. Keck Observatory in Hawaii provide data to test theories describing how small, relatively cool, but numerous “M-class” stars are born and change over time. The results will help scientists understand how the most common type of stars in the universe form in molecular clouds, and how and at what rate they develop.

Dr. Lisa Prato of Lowell Observatory used the Keck II telescope on Mauna Kea to study a sample of 33 of the youngest observable cool stars. All targets were located in the star-forming region of Ophiuchus. Dr. Prato searched for extremely close stellar pairs because they can be used to determine the relative mass of each stellar component. The observations took three years to complete and represent the largest homogenous survey of low-mass, young stars of its kind on record. Dr. Prato’s work will provide input data to help calibrate models for the early stages of star formation and evolution.

“The big product I get is a set of mass ratios, which go a long way towards testing evolutionary models,” said Dr. Prato. “Given a mass ratio and a reasonable estimate of a primary star’s mass I can take a star of a certain spectral type at a certain age and mass, and plot it on the theoretical diagrams. If the secondary star doesn’t line up with the model, then something is wrong with the model.”

Four of the 33 targets, or 12 percent of the objects, were found to be very close pairs with separations similar to – or smaller than – the Earth-Sun distance. Only a highly sensitive instrument like NIRSPEC, paired with a large-aperture telescope like Keck II, is capable of measuring the small motions induced by the binary companions to these faint stars. “Dr. Prato uses the same technique for finding binary stars as the Planet Hunters use to find planets, only she works with a different wavelength of light and uses a different instrument,” said Dr. Taft Armandroff, director of the W. M. Keck Observatory. “So this is a classic example of the type of result for which large telescopes like the Kecks were built.”

Dr. Prato’s findings are consistent with those found in previous surveys of older and more massive stars. Thus, Dr. Prato’s discoveries suggest there is no relative scarcity of the closest young, low-mass double star systems in the Milky Way Galaxy, particularly in the Ophiuchus star-forming region. The results of Dr. Prato’s survey further support a scenario for continuous star formation in Ophiuchus.

In addition, Dr. Prato serendipitously discovered five previously unknown wider double-star pairs with separations of 14 to 140 times the Earth-Sun distance. One of these is a hierarchical four-star system. There is some evidence on this basis that stars may prefer to form in multiple, hierarchal systems. With more observations in this region, Dr. Prato suspects that yet more of the closest stellar binaries and triplets might be discovered.

“I don’t think binaries will end up being the most common thing we see 50 years from now,” added Dr. Prato. “I think it will be triples or something, but we won’t know for sure until we take many more observations.”

Evolutionary models for stars similar to or a few times the mass of the Sun are fairly well understood and are supported by accurate observations. However, for stars much smaller than the Sun, the process is not as well understood. The common theory is that stars form from dense and dusty molecular clouds, composed mostly of hydrogen gas. Gravitational instability in the region causes a cloud core to collapse until the density and pressure at the core becomes so great nuclear fusion begins.

The size and temperature of the resulting star depend on the initial cloud core conditions. The extent to which these various physical forces affect the outcome of how a small, young star evolves is still under investigation. Some of the most useful evidence comes from the youngest double-star systems that can be observed with a telescope. Because the nearest star-forming regions where these objects are located are about 450 light years away, and because these stars are small and cool, the objects are intrinsically very faint. None are visible to the unaided eye, and it is essential to use a large telescope such as Keck II for such a study. The Keck Observatory’s NIRSPEC instrument is one of only a few instruments in the world able to accurately measure the mass ratios of the newly discovered close binary pairs.

The “Survey for Young Spectroscopic Binary K7-M4 Stars in Ophiuchus,” accepted for publication in the Astrophysical Journal  was funded by the National Science Foundation (AST 04-44017) and the NASA Keck PI Data Analysis Fund (JPL 1257943). Dr. Lisa Prato is the sole author of this work.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

Additional information is located at: Lowell Observatory
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First Planet-Forming Disk Found in the Environment of a Dying Star

Seattle (January 9th, 2007) Astronomers generally assume that the dusty disks where planets form are found around young stars in stellar nurseries. Now, for the first time, a protoplanetary disk has been found in the environment of a dying star.

A team of astronomers is reporting today at the winter meeting of the American Astronomical Society that material from the dying star Mira A is being captured into a disk around Mira B, its companion. Michael Ireland of the California Institute of Technology and his coauthors, John Monnier from the University of Michigan, Peter Tuthill from the University of Sydney, and Richard Cohen from the W.M. Keck Observatory, say that the finding implies that there should be many similar undiscovered systems in the solar neighborhood, providing a myriad of new places to look for young extrasolar planets.

Located 350 light years away in the constellation of Cetus, Mira (christened the “Miracle star”) first shook the foundations of the astronomy world 400 years ago with its changing brightness: visible to the naked eye for about 1 month at a time, becoming 1,000 times fainter and disappearing from view, only to re-appear again on an 11 month cycle.

“When looking at one of the most celebrated and well-studied stars in the galaxy, I was amazed to find something new and unexpected!” said Ireland. “The discovery not only changes the way we think about a star that’s important historically, but also how we’ll look at similar stars in the future.”

Although Mira was once a star very similar to the sun, it is now in its death throes as it loses its dusty outer layers at a rate of one Earth-mass every seven years. If Mira were a single star, all this material would travel into outer space. However, like two out of every three star systems, Mira has a companion star that orbits around it, in this case with a period of about 1,000 years. This companion, Mira B, has a gravitational field that catches nearly one percent of the material lost from Mira A.

By using specialized high-contrast techniques at the 10-meter Keck I telescope in Hawaii and the 8-meter Gemini South telescope in Chile, Ireland’s team discovered heat radiation coming not from Mira B itself, but also from a location offset from Mira B by a distance equivalent to Saturn’s orbit.

“Observing Mira in the infrared is like staring straight down the barrel of one of the brightest searchlights in the galaxy. It came as a real revelation to see this faint mote of dust, harboring all the possibilities of new worlds in formation, against the hostile environment of the Red Giant,” said Tuthill.

Monnier agreed, saying “Our new imaging method at Keck is revealing new details that were thought to be impossible to detect due to the blurring by atmospheric turbulence. In this case—the “detail” we discovered is potentially a whole new class of planetary system in formation!”

The intense radiation from Mira A, 5,000 times brighter than the sun, heats the edge of the disk to about Earth’s temperature and causes it to glow in the infrared. The researchers were able to show that the material was indeed the edge of a disk and not just a “clump” in the wind from Mira A. By modeling the way that this system captures the outflow from Mira A, the researchers were also able to confirm that Mira B is simply an ordinary star like the sun, although about half as massive.

The key part of this result is what will happen when Mira A finishes its death throes and becomes a white dwarf in about one million years. The disk-creating process will have finished and the disk itself will be capable of forming new planets. “The expected abundance of this kind of system means a new way to find planets that we know are young around stars like our sun, ” Ireland says.

Astronomers associate the death of a star with the death of its planetary system. Here, the opposite is happening. “An aging star is laying the foundation for a new generation of planets, ” says Ireland. “This is Greek tragedy on a cosmic scale.”

Similar systems could be discovered and studied by future telescopes such as the Thirty Meter Telescope

The work was supported by the Australian Research Council and the NASA Navigator program.

Press Release Courtesy of Caltech

First Triple Quasar Discovered at W. M. Keck Observatory

Seattle (January 8th, 2007) Astronomers using the W. M. Keck Observatory have discovered a triple quasar.

Quasars are powerful sources of electromagnetic energy, which includes radio waves and light. They are believed to be powered by supermassive black holes in the centers of galaxies.

While roughly 100,000 quasars and dozens of double quasars have been observed in recent years, the discovery by scientists at the California Institute of Technology and Ecole Polytechnique Federale de Lausanne (EPFL) in Switzerland is the first involving quasars from three relatively close galaxies.

It also shows how large telescopes like the twin instruments operated by the Keck Observatory atop Mauna Kea are furthering humankind’s understanding of the universe.

“As more binary and triple quasar systems are discovered, science will have a new tool with which to understand how galaxies and supermassive black holes in the distant universe may have developed and changed over time,” said Dr. Taft Armandroff, director of the W. M. Keck Observatory. “This is an area of research for which large telescopes like Keck I are well-suited.”

S. George Djorgovski, a Caltech professor and the leader of the team which made the discovery, said quasars are thought to be powered by gas falling into the black holes, a process believed to be enhanced when galaxies collide. The triple quasar is located about 10.5 billion light years away – a time when galaxy interactions were at their peak, Djorgovski said.

Such a mingling of galaxies would explain the increasing number of double or binary quasars discovered in recent years as well as the presence of the triple quasar, according to Ashish Mahabal, another Caltech scientist involved in the discovery.

Although quasars are extremely bright, capable of producing more light than an entire galaxy of a hundred billion stars, their massive energy comes from an area smaller than our solar system.

The latest discovery began modestly in 1989 with the finding of a distant quasar named LBQS 1429-008 by astronomers at Cambridge in England. The astronomers, led by Dr. Paul Hewett of Cambridge’s Institute of Astronomy, also found a fainter quasar in the same area.

However, Hewett and his colleagues at first believed the second quasar to be a case of gravitational lensing. That concept, proffered by Albert Einstein in his theory of relativity, involves a large mass such as a cluster of galaxies which can cause a light image to split, in essence creating a double image. But research over the past several years has prompted astronomers to propose that the find was actually a pair of close quasars.

And then a third, even fainter quasar was found using observations from one of Keck’s twin 10-meter telescopes combined with measurements from the European Southern Observatory’s 8.2-meter Very Large Telescope located in Chile.

Extensive computer modeling carried out by Djorgovski’s research team appears to rule out the possibility that the triple quasar could be the product of gravitational lensing. They also were unable to find any galaxy which could be producing such a lensing phenomenon. In addition, the team was able to document small but significant differences in the properties of the three quasars, lending further credence to the belief they are separate entities.

Additional information is posted to Dr. George Djorgovski’s Web site at: http://www.astro.caltech.edu/~george/qqq/

The findings were reported at the January 8th meeting of the American Astronomical Society in Seattle. A paper describing the research also has been submitted to the Astrophysical Journal Letters. Other co-authors include Prof. Georges Meylan, leader of the portion of the team from Ecole Polytechnique Fédérale de Lausanne in Switzerland which included Dr. Domonique Sluse; Dr. Eilat Glikman of Caltech; and Dr. David Thompson, an astronomer at the University of Arizona’s Large Binocular Telescope Observatory.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy. CARA is a non-profit corporation with a governing board consisting of directors from the California Institute of Technology and the University of California. Input to the board is provided by the National Aeronautics and Space Administration, better known as NASA, and by the Los Angeles-based W.M. Keck Foundation which provided grants of more than $140 million to build the twin Keck telescopes and support facilities. The W.M. Keck Observatory, which has its headquarters in Waimea, has an annual operating budget of $11 million and 125 full-time employees, making it one of Waimea’s biggest employers.

Astronomers Discover Enormous Halo of Red Giant Stars Orbiting Andromeda

Seattle (January 7th, 2007) Astronomers have found an enormous halo of stars bound to the Andromeda galaxy and extending far beyond the swirling disk seen in images of the famous galaxy, our nearest large galactic neighbor. The discovery, reported at the American Astronomical Society meeting in Seattle, suggests that Andromeda is as much as five times larger than astronomers had previously thought.

“I am absolutely astounded by how big this halo is. As we looked farther and farther out, we kept finding stars that look like halo stars,” said Puragra (Raja) Guhathakurta, professor of astronomy and astrophysics at the University of California, Santa Cruz, who will present the findings at the meeting.

Guhathakurta and his collaborators at UCSC, UCLA, and the University of Virginia are conducting an ongoing study of Andromeda’s stellar halo, using observations at the Kitt Peak National Observatory in Arizona and the W. M. Keck Observatory in Hawaii. Their new findings are based on data gathered using the 4-meter Mayall Telescope at Kitt Peak and the DEIMOS spectrograph on the 10-meter Keck II Telescope in Hawaii.

The researchers detected a sparse population of red giant stars—bright, bloated stars in a late stage of stellar evolution—that appear to be smoothly distributed around the galaxy out to a distance of at least 500,000 light-years from the center. Even at that great distance, the stars are bound to the galaxy by gravity. These stars probably represent Andromeda’s stellar halo, a distinct structural component of the galaxy that has eluded astronomers for over 20 years, Guhathakurta said.

Following up on their discovery of Andromeda’s halo, the researchers have found evidence that stars in the halo are chemically anemic compared with stars in the inner parts of the galaxy, said Jasonjot Kalirai, a postdoctoral fellow at UCSC. The halo stars are “metal-poor,” meaning they contain smaller amounts of the heavier elements, a finding that is consistent with theoretical models of galaxy formation, Kalirai said.

Andromeda (also known as M31) is a large spiral galaxy very similar to our own Milky Way. While it is difficult for astronomers to study the overall structure of the Milky Way from Earth’s vantage point within it, Andromeda offers a global view of a classic spiral galaxy that is close enough for astronomers to observe individual stars within it. Andromeda is about 2.5 million light-years from Earth and is the largest galaxy in the “Local Group,” which also includes the Milky Way and about 30 smaller galaxies.

“The physical size of this galaxy is really striking,” said coauthor R. Michael Rich of UCLA. “The suburbs of M31 and the Milky Way are so extended that they nearly overlap in space, despite the great distance between these two galaxies. If the whole of M31 were bright enough to be visible to the naked eye, it would appear to be huge, larger in apparent size than the Big Dipper.”

Spiral galaxies typically have three main components: a flattened disk, a bright central bulge with a dense concentration of stars, and an extended spherical halo of sparsely distributed stars. The concentration of stars in the central bulge decreases exponentially with increasing distance from the center, whereas the density of the halo stars falls off more gradually (as an inverse power of the radius).

In Andromeda, the disk has a radius of about 100,000 light-years. Outside the plane of the disk, stars plausibly belonging to the central bulge can be found as far out as 100,000 light-years from the center of the galaxy, while the halo extends five times farther than that, according to Guhathakurta.

“We now believe that previous groups have been mistakenly identifying the outer parts of the Andromeda bulge as its halo,” he said.

Guhathakurta’s group was able to detect the halo by developing a sophisticated technique for clearly distinguishing halo stars in Andromeda from the more numerous foreground stars in the Milky Way. A foreground star with low luminosity and a luminous star that is much farther away can be hard to tell apart because they appear to be equally bright from our perspective, Guhathakurta said.

“A firefly 10 feet away and a powerful beacon in the distance can have the same apparent brightness. In this case, the fireflies are dwarf stars in our own galaxy and the beacons are red giant stars in Andromeda,” he said.

Karoline Gilbert, a UCSC graduate student, developed the technique for separating the fireflies from the beacons. Her technique provided a clear separation between the two populations of stars by combining five diagnostic criteria based on photometry (brightness measurements) and spectroscopy (which separates starlight into a spectrum of different wavelengths). The diagnostic criteria include radial velocity and parameters based on differences in surface gravity between red giants and dwarf stars.

“We focused on detecting red giant stars in the halo because they are bright enough for us to obtain spectra,” Gilbert said. “There are assuredly other kinds of stars in Andromeda’s halo, but they are just too faint for us to get spectra of them.”

In addition to Gilbert, Guhathakurta, Kalirai, and Rich, the other collaborators include Steven Majewski, James Ostheimer, and Richard Patterson at the University of Virginia and David Reitzel at UCLA.

The group’s ongoing investigation of Andromeda’s halo promises to shed new light on the question of how large galaxies formed, Guhathakurta said.

“Galaxy formation theories tell us that halos are pristine—the oldest component of the galaxy—but this is based almost entirely on studies of our own galaxy. A detailed study of this newly discovered Andromeda halo will allow us to test whether these theories apply more generally to galaxies other than the Milky Way,” he said.

Press Release Courtesy of UC Santa Cruz

Newfound Diversity in Gamma-Ray Bursts

Berkeley (December 20th, 2006) Two brilliant flashes of light from nearby galaxies are puzzling astronomers and could indicate that gamma-ray bursts, which signal the birth of a black hole, are more diverse than once thought.

The two new gamma-ray bursts are of the long variety but, surprisingly, did not show any evidence of supernova activity. This flies in the face of what was an emerging consensus about the origin of long bursts, according to University of California, Berkeley’s Joshua Bloom, assistant professor of astronomy. To Bloom, this indicates that there are more than two ways to produce a gamma-ray flash and a black hole.

“Instead of simplicity and clarity, we’re seeing a rich diversity emerge - there are more ways than we thought for producing flashes of gamma-rays,” Bloom said.

Bloom and 30 colleagues from around the world report observations of two of these peculiar gamma-ray bursts, labeled GRB 060505 and GRB 060614, in the Dec. 21 issue of the British journal Nature. Three other papers in the same issue report details of GRB 060614. Both bursts were detected by NASA’s Swift satellite - the first on May 5, 2006, the second on June 14, 2006.

Based solely on GRB 060614, many astronomers remained skeptical about the need to cast away the tidy connection of long bursts to supernovae. Yet, as Bloom stated, “It’s easy to explain away one of these anomalous events as a fluke, but two strange events give our claim some oomph. These events are observational threats to the one-to-one association between long bursts and supernovae.”

The whole story started with a non-discovery. Daniel Perley, a graduate student in astronomy at UC Berkeley, suggested that he and Bloom use the Keck I telescope in Hawaii to observe an area of sky where the long burst GRB 060505 had been seen in May. That long burst lasted four seconds and was pinpointed inside a galaxy a little over 1 billion light years away, towards the constellation Piscis Austrinus.

Had this flash been associated with the kind of supernova typically seen at sites of long gamma-ray bursts, or even a relatively weak supernova down to 250 times less powerful, the Keck telescope would have detected it, but instead Bloom and Perley observed nothing but the parent galaxy.

“We usually learn a lot about an event when new sources are detected, but in this context, it was much more exciting to detect nothing,” Perley said.

At around the same time, a Danish group headed by Johan Peter Uldall Fynbo of the Neils Bohr Institute at the University of Copenhagen had had similar lack of success finding a supernova associated with GRB 060614. That burst lasted almost two minutes and was pinpointed near a galaxy 1.6 billion light years away, towards the constellation Indus. In both cases, the presence of obscuring dust was ruled out.

Fynbo gathered data from an international team, including Bloom and Perley, which argued in the Nature paper that the two supernovae together suggest a “new phenomenological type of massive stellar death.”

Most astronomers have concluded that some new process must be at play: either the model of mergers creating second-long “short” bursts needs a major overhaul, or the progenitor star from this peculiar explosion is intrinsically different from the kind that make supernovae and long bursts.

“The paradigm had emerged that all long bursts were associated with the death of massive stars,” said Bloom, who last year discovered evidence that convincingly linked short-lived gamma-ray bursts to the explosive merger of old, dead stars. The new observations “do not rule out a massive star origin, but does require that supernovae produced in some explosions are either very weak or non-existent.”

Swift, launched in November 2004, is a NASA mission managed by NASA Goddard in partnership with the Italian Space Agency and the Particle Physics and Astronomy Research Council of the United Kingdom.

Aside from Fynbo, Bloom and Perley, authors of the paper include National Science Foundation postdoctoral fellow Daniel Kocevski of UC Berkeley. The UC Berkeley and Copenhagen groups are collaborating as part of an international consortium of 10 elite universities called the International Alliance of Research Universities.

First seen 40 years ago, gamma-ray bursts are the brightest explosions in the universe. They appear to fall into two distinct categories, short and long, depending on whether they shine for less than or more than about two seconds. Observations accumulated over the last decade led to a consensus that the long variety occurred when a massive star at the end of its life collapses to form a black hole. In addition to making a burst of gamma-rays, the explosion also produces a bright supernova. The short ones, not accompanied by a supernova, are thought to herald the merger of two neutron stars or a neutron star and a black hole, resulting in a bigger black hole.

News Release Provided by: UC Berkeley

NSF Awards $2 Million Grant to Improve Keck Interferometer

Kamuela (December 18th, 2006) The National Science Foundation (NSF) has awarded the W. M. Keck Observatory $2 million to improve the sensitivity and resolution of the Keck Interferometer. The improvements will enable the instrument to detect Jupiter-sized planets around other stars and test predictions of Einstein’s general theory of relativity in the chaotic core of our galaxy.

The three-year grant is from NSF’s Major Research Instrumentation Program (MRI), which each year funds more than 200 proposals to develop or purchase scientific instrumentation. Typically, less than one-half of one percent of all submitted proposals receive the maximum award of $2 million, and only a couple go to astronomical observatories.

“The interferometer improvements will make Keck Observatory a unique instrument for measuring the position, velocity and acceleration of stars near the massive black hole at the center of our own galaxy, allowing us to look for the distortions in space predicted by general relativity,” said Principal Investigator Dr. Peter Wizinowich, a senior scientist at the W. M. Keck Observatory.

The money will be used to boost the sensitivity of the 85-m baseline Keck Interferometer which combines the light from the two 10-meter diameter Keck telescopes. Combined with Laser Guide Star Adaptive Optics on both Keck telescopes, the improvements will allow the linked Keck telescopes to observe objects 100 times fainter than the existing interferometer and measure the apparent positions of celestial objects with 10 times more accuracy than a single Keck telescope working alone.

Observations near the black hole at the center of the galaxy “are at the core of the project and will be difficult and technically challenging,” said Project Scientist James R. Graham, professor of astronomy at the University of California, Berkeley.

Even before this goal is achieved, the upgrades will allow the Keck Interferometer to help determine the mass of extra-solar planets by measuring the periodic change in the position of parent stars caused by the tug of unseen planets. Currently, more than 200 extra-solar planets have been detected due to the radial velocity or “wobble effect” they induce on their parent star. About two-thirds of all known extra-solar planets have been confirmed at the W. M. Keck Observatory. The Interferometer will add precise orbital measurements to the existing catalogue of radial velocity data to help precisely determine the mass of extra-solar planets the size of Jupiter and larger.

Extra-solar planets and dusty stellar disk observations were a major goal of the interferometer when NASA’s Origins program funded its development in support of upcoming planet-finding missions. Now that NASA has temporarily shelved these missions—the Space Interferometer Mission and the Terrestrial Planet Finder— the Keck Interferometer will be the only instrument in the world capable of measuring accurate masses for planets around distant stars.

The grant funds two major telescope improvements: installation of a phase referencing system on the interferometer that will allow longer exposures, and thus detection of fainter objects; and upgrading of the interferometer to be able to perform accurate measurements of a star’s position.

Phase referencing is an interferometric technique in which two or more receivers simultaneously look at the same reference star or galaxy and compares signals. The process makes it possible for the instrument to adjust the signal from each telescope just the right amount to cancel out any wavelength differences caused by atmospheric turbulence, or “seeing.”

Phase referencing provides a stable image which will allow the Keck Interferometer to track an object 100 to 500 times longer than before. The extended exposure time will allow the instrument to study much fainter objects, such as the cores of active galactic nuclei that signal the presence of a central black hole.

The second part of the project will develop the interferometer’s ability to accurately measure positions of celestial objects. Improvements will be made to the existing metrology systems and the instrument’s ability to accurately measure the relative positions of the two Keck telescopes.

A key goal of the project, Dr. Wizinowich added, is to demonstrate the power of combining laser guide star adaptive optics with interferometry to observe faint science objects.

With the added improvements, the Keck Interferometer will resolve objects on the sky to an accuracy of 30 microarcseconds, compared to about 300-microarcsecond resolution of each telescope alone. Such fine measurements will allow scientists to measure the velocities of stars orbiting the black hole at the center of the galaxy.

The hope, Dr. Graham said, is to detect in the stellar orbits the effect of the dragging of “inertial reference frames” predicted to occur near a rapidly rotating black hole. This effect is predicted by Newton’s laws of motion for mass located very near a spinning black hole. Scientists using the Keck Interferometer may be able to see this effect, which would be major breakthrough in tests of general relativity and other theories of gravity. The observations could also prove that black holes spin, thus constraining theories of their formation.

“This is a major opportunity to show astronomers what interferometry can do for them,” Wizinowich said. “Every time astronomers look in more detail at the sky, they learn something new.”

Scientific collaborators on the NSF proposal for development of the Keck Interferometer with Laser Guide Star Adaptive Optics for Microarcsecond Astronmetry—from Exoplanets to Black Holes— include: Dr. Julien Woillez at the W. M. Keck Observatory, Dr. Andrea Ghez at the University of California at Los Angeles; Dr. Rachel Akeson and Dr. Lynne Hillenbrand of the California Institute of Technology; Dr. Josh Eisner and Dr. Eliot Quataert of University of California at Berkeley; Dr. Nevin Weinberg, University of California at Santa Barbara and Dr. John Monnier at the University of Michigan.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose governing board consists of directors from the California Institute of Technology and the University of California. In addition, the National Aeronautics and Space Administration and the W. M. Keck Foundation each have liaisons to the board. Construction of the twin Keck telescopes and domes was made possible with generous grants totaling more than $140 million from the W. M. Keck Foundation in Los Angeles.

Images of Dwarf Planet Ceres

Pasadena, Calif. (October 11th, 2006) Although Ceres is the largest main-belt asteroid and was the first to be discovered (by G.Piazzi in 1801), its physical properties are still not well understood. While it is expected to have retained a large amount of primordial water ice in its interior, many questions about the composition of its surface and sub-surface layers, the properties of its regolith and its degree of differentiation, remain unanswered.

A team of astronomers led by Benoit Carry of the Paris-Meudon Observatory used state-of-the-art adaptive optics instrumentation available at the Keck observatory, Mauna Kea, Hawaii, to image the surface of Ceres with a spatial resolution of ~30km. The observations were carried out during the September 2002 opposition of Ceres in the near-infrared J/H/K-bands, at a wavelength range particularly well adapted to investigate the composition and properties of planetary surfaces. The team produced albedo maps covering 80 percent of the asteroid, which appears to display a wealth of 40 to 160km large geological features with intensity in reflected light varying by ~12 percent across the surface. The team suggests that the variations could be due to terrain features, as well as differences in their surface composition and/or degree of alteration by space weathering effects (such as aging of surface due to interaction of solar wind, micrometeorites impacts, etc).

The team also derived measurements of the dimension and shape of the dwarf planet Ceres, which can be considered as an oblate spheroid of radii a=481km and b=447km (uncertainty of +/-14 km). The direction of its spin axis in a J2000 coordinate referential is right ascension=287 degrees and declination=69 degrees (5 degrees of
incertitude). These two results are in agreements with earlier
reports made by Thomas et al. (Nature 2005) from the analysis of
Hubble Space Telescope observations.

Additional spatially resolved spectroscopic observations are needed to investigate further the properties of Ceres surface. Such programs will help in the preparation of the NASA DAWN mission, which will reach Ceres in 2015 and explore, from orbit, the properties of this intriguing solar system body. The team is currently planning complementary observations of Ceres during its next opposition in November 2007, using a suite of adaptive optics instruments at the Very Large Telescope of the European Southern Observatory in Chile.

Press Release Provided by: AAS Division of Planetary Sciences

Keck Observatory’s Ben Berkey Named Volunteer of the Year

Hale Pohaku, Mauna Kea (September 23rd, 2006) The Mauna Kea Visitor Information Station (VIS) annual Volunteer Appreciation Banquet took place at Hale Pohaku on September 23, 2006. Forty-four volunteers joined in the celebration.

Special awards were presented at the banquet. Keck Observatory employee Benjamin Berkey was named Volunteer of the Year with his amazing lifetime dedication of 1,218 hours of volunteer service. Mr. Berkey started volunteering as a UHH student, gaining excellent hands-on astronomy experience. Since then he has earned a position in the optics group at the W. M. Keck Observatory. Joshua Williams was named the Most Dedicated Volunteer, generously giving 458 volunteer hours last year alone. Mr. Williams is a senior astronomy student at UHH. Clifford Livermore received the Hoku award in recognition of his dedication of 1,014 lifetime volunteer hours. Mr. Livermore is a community volunteer/amateur astronomer from Waikoloa. He was one of the original 27 volunteers of the VIS back in 1999.

The volunteer program started on Mauna Kea in 1999 with a small but dedicated group of 27 volunteers. From this humble beginning, great things have grown. The volunteer program has multiplied more than six times that size with 171 active volunteers last year.

Volunteers assist on the mountain in a variety of ways. For those who are interested in the stars, they come and work as celestial guides during the free nightly stargazing program at the VIS from 6-10p. For those who are interested in the observatories, they come and work as tour guides during the free escorted summit tours every weekend. For those who are interested in the environment of the mountain, they come and work to maintain the hiking trails on the mountain. For those who are interested in the cultural aspects of Mauna Kea, they come and work as cultural guides at the VIS. Volunteers represent all facets of Mauna Kea and are a true reflection of the mountain.

“Volunteers love coming to the mountain. There’s something really special about this place. Volunteers serve a critical role in bringing the VIS programs to fruition but they also have a great time while they are here,” remarked Patti Gomas, Volunteer Coordinator at the VIS.

Volunteers at Mauna Kea come from all walks of life. University of Hawaii students contributed the majority (60%) of volunteer hours last year. Community volunteers (26%), retirees (11%), and astronomers (3%) made up the difference. Gomas went on to explain, “The university community has always been an important part of our volunteer audience. However, we have seen an interesting shift over the last year within the community. We have had record dedication by our community volunteers and retirees. More than ever the interest in Mauna Kea is thriving.”

This year’s banquet was dedicated to the memory of John Altonn. Mr. Altonn was an extremely active retiree volunteer who passed away this past year. He led hundreds of guests to the summit and freely shared his knowledge and passion for Mauna Kea. Phyllis Altonn joined in the celebration and was touched with a presentation of a memorial poster from the volunteers who worked with her husband.

Volunteers are always welcome. Applications to become a Mauna Kea volunteer can be obtained online at http://www.ifa.hawaii.edu/info/vis or in person at the Visitor Information Station.

‘Champagne Supernovae’ Challenges Ideas About How Supernovae Work

Pasadena, Calif. (September 20th, 2006) An international team of astronomers at the California Institute of Technology, University of Toronto, and Lawrence Berkeley National Laboratory have discovered a supernova more massive than previously believed possible. Observations of the supernova were obtained at the Canada-France-Hawaii telescope and the Keck telescope, both located on Mauna Kea in Hawaii. The result has experts rethinking their basic understanding of how stars explode as supernovae, according to a paper to be published in Nature on September 21.

The lead author of the study, University of Toronto postdoctoral researcher Andy Howell, identified a Type Ia supernova, named SNLS-03D3bb, in a distant galaxy 4 billion light years away that originated from a dense evolved star, termed a “white dwarf,” whose mass is far larger than any previous example. Type Ia supernovae are thermonuclear explosions that destroy white dwarfs when they accrete matter from a companion star.

The discovery was made possible through images taken as part of a long-term survey for distant supernovae with the Canada France Hawaii Telescope. Follow-up spectroscopy led by Richard Ellis, Steele Family Professor of Astronomy at Caltech, with the 10-meter Keck Telescope was key to determining the unusually high mass of the new event.

Researchers say the surprisingly high mass of SNLS-03D3bb has opened up a Pandora’s box on the current understanding of Type Ia supernovae and, in particular, how well they might be used for future precision tests of the nature of the mysterious “dark energy” responsible for the acceleration of the cosmic expansion.

Current understanding is that Type Ia supernova explosions occur when the mass of a white dwarf approaches 1.4 solar masses, or the “Chandrasekhar limit.” This important limit was calculated by Nobel laureate Subramanyan Chandrasekhar in 1930, and is founded on well-established physical laws. Decades of astrophysical research have been based upon the theory. Yet somehow the star that exploded as SNLS-03D3bb reached about two solar masses before exploding.

“It should not be possible to break this limit,” says Howell, “but nature has found a way! So now we have to figure out how nature did it.”

In a separate “News & Views” article on the research in the same issue of Nature, University of Oklahoma professor David Branch has dubbed this the “Champagne Supernova,” since extreme explosions that offer new insight into the inner workings of supernovae are an obvious cause for celebration.

The team speculates that there are at least two possible explanations for how this white dwarf got so fat before it went supernova. One is that the original star was rotating so fast that centrifugal force kept gravity from crushing it at the usual limit.

Another is that the blast was in fact the result of two white dwarfs merging, and that the body was only briefly more massive than the Chandrasekhar limit before exploding.

Since Type Ia supernovae usually have about the same brightness, they can be used to map distances in the universe. In 1998 they were used to make the surprising discovery that the expansion of the universe is accelerating. Although the authors are confident that the discovery of a supernova that doesn’t follow the rules does not undermine this result, it will make them more cautious about using them to measure distance in the future.

Ellis summarizes: “This is a remarkable discovery that in no way detracts from the beautiful results obtained so far by many teams, which convincingly demonstrate the cosmic acceleration and hence the need for dark energy. However, what it does show is that we have much more to learn about supernovae if we want to use them with the necessary precision in the future. This study is an important step forward in this regard.”

Peter Nugent a staff scientist with the of the scientific computing group at Lawrence Berkeley National Laboratory is a co-author.

W. M. Keck Observatory Science Meeting Takes Place September 15 at UC Irvine

Kamuela (September 5th, 2006) Science reporters are invited to attend the annual Keck Observatory Science Meeting on Friday, Sept. 15 at University of California, Irvine. The meeting features recent results from the Keck I and Keck II 10-meter telescopes on Mauna Kea. The meeting also provides reports on existing instrumentation and the status of future instrumentation. This will be the first opportunity for the Keck user committee to meet Director Taft Armandroff, who took office July 1, 2006.

Participants at the Keck Science Meeting include Observatory staff and astronomers from Caltech, University of California, NASA, NOAO’s TSIP program and others who use Keck Observatory in their research.

MEETING FORMAT
Presenters will have 15-minutes to summarize recent results. Science writers are welcome between 8:45am and 7:30 p.m. Friday, Sept. 15th only. Review the schedule in advance at:
http://www.physics.uci.edu/~barth/ksm2006/talks.html.

Poster sessions will showcase current research. A list of registered posters is online at: http://www.physics.uci.edu/~barth/ksm2006/posters.html.

MEDIA REGISTRATION
Access to the Keck Observatory Science Meeting is by invitation only for the Sept. 15th session. Qualified science reporters must contact the W. M. Keck Observatory Public Information Officer, Laura Kinoshita, before Wed., Sept. 12th to obtain credentials. Interviews may be scheduled in advance. A list of the 127 registered participants is available upon request.

The Keck Science Meeting 2006 is sponsored by the W. M. Keck Observatory and the Institute for Geophysics and Planetary Physics of the University of California.

Elegant spiral arms betray existence of massive binary stars within bright star cluster

Kamuela, Hawaii (August 22nd, 2006) – The five red stars at the heart of the Quintuplet Cluster – one of the most massive clusters in the Milky Way Galaxy – may all be dusty pinwheels, a strange but beautiful type of nebula only recently recognized.

Two of the five have been imaged in the near infrared with the W. M. Keck Observatory’s 10-meter Keck I telescope on Mauna Kea in Hawai’i, and display the pinwheel shape characteristic of two stars rotating around one another and spewing out dust in a spiral arc in the same way a rotating lawn sprinkler creates a water spiral.

Dubbed colliding wind binary “pinwheel” nebulae, they are exotic rarities found only among the most massive binary stars approaching the ends of their lives, according to astrophysicist Peter Tuthill of the University of Sydney, Australia. Tuthill led the group that published images in the Aug. 18 issue of Science of the two confirmed pinwheels in the Quintuplet Cluster.

The discovery of two and perhaps five massive binaries in a young, bright cluster suggests that many of the very luminous stars in our galaxy – most of which are surrounded by dust—harbor massive binaries, not single stars. This would have implications for our understanding of supernova explosions and the brightness and evolution of stars, according to Tuthill.

Massive stars – in the case of the five bright stars of the Quintuplet Cluster, between 10 and 20 times the mass of our sun—live fast and die young. Perhaps only a few million years old, the five brightest stars in the Quintuplet Cluster have essentially blown off all the hydrogen in their envelopes and are nude helium stars fusing helium into heavier elements in the core. Called Wolf-Rayet stars, they have strong stellar winds that, in a binary system of two such massive stars, collide and generate copious dust. The cool dust nursery at the collision front between the stellar winds is carried around with the natural orbital motion of the two stars, trailing dust as it turns. In the case of one of these stars, the spiral covers 300 astronomical units, or 300 times the radius of Earth’s orbit.

“Wolf-Rayet stars are very compact and hot, driving off intense stellar winds,” he said. “But because they are shrouded in dust, you could never observe whether there is a binary at the core. When you see this elegant spiral tail of gas and dust, however, it tells you immediately that you’re looking at a colliding wind binary.”

The Quintuplet Cluster is less than 100 light years from the core of the Milky Way Galaxy, located 25,000 light years from Earth in the constellation Sagittarius. Estimated to be about 4 million years old, the cluster’s massive young stars shine brighter than any cluster in the galaxy. Though obscured by dust until 1990, infrared imaging has since revealed the five brightest stars to be 10,000 to 100,000 times brighter then the sun. These stars typically have brief lives that end in explosive supernovae or hypernovae.

With a mass greater than 10,000 suns, the Quintuplet Cluster is 10 times larger than typical young star clusters scattered throughout the Milky Way and is destined to be ripped apart in just a few million years by gravitational tidal forces in the galaxy’s core. It also is the home of the brightest star seen in the Galaxy, called the Pistol star.

Images of the cluster taken in 1997 by the Hubble Space Telescope’s near-infrared camera, NICMOS, showed the five brightest stars for which the cluster is named as bright red dusty points of light, according to Tuthill. Using speckle interferometry with the near-infrared camera on Keck I in 1998 and 1999, he and his colleagues obtained five times greater resolution than Hubble, enabling them to see the actual spiral dust cloud in two of the five stars.

“With five times greater resolution on the Keck Telescope, we could really focus in on the core of the star and drill deep down into the physics of these massive stars, finally answering the mystery of what these enigmatic cocoon stars are,” he said.

Tuthill and colleagues William C. Danchi and John Monnier, all then at the University of California, Berkeley’s Space Sciences Laboratory, reported the first such spiral nebula in 1999 associated with the binary star system WR 104. Danchi, now at the NASA Goddard Space Flight Center in Houston, and Monnier, now an assistant professor of astronomy at the University of Michigan, Ann Arbor, are coauthors on the current Science paper, along with Angelle Tanner of the Jet Propulsion Laboratory in Pasadena, Donald Figer of the Rochester Institute of Technology, and Andrea Ghez of the University of California, Los Angeles.

Massive stars like those in the Quintuplet Cluster are important because, though they typically make up only a few percent of the stars in a galaxy – that is, a few hundred or thousand stars out of billions – they outshine all the other stars put together. They also exert a strong influence on other stars because of their intense stellar winds, which produce shock waves that compact dust and gas into new star-forming regions, or disrupt such regions to stall star formation.

“These massive stars shove everything around with their strong winds, exerting a big influence on the evolution of the galaxy as a whole,” Tuthill said.

They also seed the galaxy with heavy elements when they explode. Binary systems like those in the Quintuplet Cluster are destined for three supernova explosions: each star separately, possibly producing a brilliant “long” gamma-ray burst and leaving behind a neutron star or black hole; and a third time when the two compact objects spiral into one another and merge in an explosion thought now to generate “short” gamma ray bursts.

From their observations, Tuthill calculated that one of the binary star pairs is separated by a couple of astronomical units (AU), where an AU is the average distance between the Earth and Sun: 93 million miles. They orbit one another every 750-950 days.

While they were unable to see structure within the dust enshrouding the three other bright stars of the cluster, all show similar characteristics to the two pinwheel nebulae. Tuthill suspects that they too are colliding wind binaries, either too tightly wound to resolve or tipped at an angle such that the spirals are obscured.

Colliding-wind pinwheels should leave a signature in the afterglow of a supernova explosion of one of the two stars in the binary, Tuthill noted, as the expanding shockwave encounters the spiral arms. In 2004, Stuart D. Ryder, a staff astronomer at the Anglo-Australian Observatory, reported ripples in the light curve of one supernova (SN2001ig) that may have been caused by such a mechanism in a colliding-wind binary.

The work was supported by the Australian Research Council and the National Science Foundation.

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea on the island of Hawai’i and is managed by the California Association for Research in Astronomy, a non-profit corporation whose board of directors includes representatives from the California Institute of Technology, the University of California and NASA. For more information, please visit http://www.keckobservatory.org.

Internship Program Wraps with Student Symposium at ‘Imiloa Astronomy Center

Hilo, Hawaii (August 2nd, 2006) – The ‘Imiloa Astronomy Center in Hilo, which is dedicated to showcasing astronomy and culture in Hawaii, was an ideal venue for the 2006 Akamai Observatory Internship Symposium on Friday, July 28.

In the center’s planetarium, usually a venue for celestial star shows, 13 stars from the educational universe were seated in the front row. Although they had each successfully overcome serious challenges during their eight-week internships at an astronomical institution or observatory, they were still nervous as they presented the results of the projects they worked on to a gathered audience of mentors, colleagues, friends and family.

Under the cool blue light of the planetarium dome, Lisa Hunter welcomed the audience and introduced herself as Education Director at the Center for Adaptive Optics, a National Science Foundation Science and Technology Center (CfAO) at the University of California, Santa Cruz, which funds the Akamai Internship Program on the island of Hawaii. The program, now in its third year, places university and community college students with mentors at Big Island observatories for a paid, project-based summer internship. The students all have Hawaii ties and are studying some aspect of science, engineering or technology.

The first speaker, Cherie Kinoshita is a sophomore this year at the University of Hawaii at Manoa, majoring in mechanical engineering. Cherie grew up on Oahu, where among other activities she is an assistant coach for high school varsity girl’s basketball. As Cherie accepted a lei and a quick hug from Malika Bell, the program’s communication instructor, the first slide of her presentation appeared large and bright on the dome above her. Cherie told the audience that she had worked under the guidance of Billie Chitwood at the Smithsonian Submillimeter Array. During her 10-minute talk, she explained how she used a strain gauge to collect data to help determine whether door cutouts in the base of the antennas are affecting their performance.

Next up was Jennifer Takaki, a Hawaii Community College Electronics Technology student, who currently works as a student electronics technician at the Subaru Telescope. She designed and built a system to remotely control Subaru’s helium compressors. In the introduction to her talk she explained how the program had given her the opportunity to be responsible for a single project from design through fabrication and testing, as opposed to her normal isolated task-based work. She said, “I have a different perspective now, seeing all the steps that a project needs to go through to get done. I think I will look at all my work differently now”

The thirteen students interned at six different Hawaii Island institutions; the W. M. Keck and Gemini Observatories, the Subaru Telescope, the Institute for Astronomy, the Smithsonian Submillimeter Array and the Ashra Detector Project, a collaboration between the University of Hawaii and the University of Tokyo.

The program’s goals include introducing Hawaii students to careers in astronomy, helping to develop a locally based high-tech workforce and promoting collaboration among the observatories and educational institutions on Hawaii.

Other student projects included developing a database for storing and retrieving observatory images, creating several different computer interfaces for telescope control and data analysis, fabricating and testing detectors and detector controllers, analyzing the oils and fluids used by the telescopes for predictive maintenance, as well as designing and fabricating an improved hatch door to isolate sensitive telescope optics.

In addition to the internship experience, the Akamai program also provides the students with a strong communication component through on-going support and weekly group meetings. Along with the final presentations, they also each produced a poster on their project, updated their resumes and prepared personal statements with the guidance of CfAO education staff.—Story by Sarah Anderson

Contact: For further information, see http://cfao.ucolick.org/EO/internshipsnew/akamai or call Sarah Anderson, Hawaii Island coordinator for Akamai, at (808) 881-3839.

Keck telescope captures Jupiter’s Red Spot Jr. as it zips past planet’s Great Red Spot

Kamuela, Hawaii (July 29th, 2006) – Astronomers from the University of California, Berkeley, and the W. M. Keck Observatory in Hawaii this month snapped high-resolution near-infrared images of the Great Red Spot, a persistent, high-pressure storm on Jupiter, as a smaller storm, Red Spot Jr., breezed by it on its race around the planet.

The image, which also shows Jupiter’s moon Io, was taken on July 20 Hawaii time (July 21 Universal Time) by the Keck II telescope on Mauna Kea using adaptive optics (AO) to sharpen the image.

The spots are of interest to astronomers because Red Spot Jr. formed from the merger of three white spots only recently, between 1998 and 2000, and in December 2005 turned red like the much older Great Red Spot. While the new red spot is about the size of Earth, the Great Red Spot is nearly twice that diameter and has been circling the planet for at least 342 years.

The images captured by the second-generation Near Infrared Camera (NIRC2) on Keck II show that, though the two red spots are about the same color when seen in visible wavelengths (see Christopher Go’s optical image from July 20 UT), they differ markedly at infrared wavelengths. When the astronomers viewed the planet through a narrow-band filter centered on the 1.58 micron, near-infrared wavelength, Red Spot Jr., which was called Oval BA before it changed from white to red, was a lot darker, indicating that the tops of the storm clouds may be lower than those of the Great Red Spot. With more atmosphere above its cloud tops, more infrared light is absorbed by molecules like methane in the atmosphere.

“Red Spot Jr. is either not as high as the Great Red Spot, or it’s just not as reflective, that is, as dense,” said lead astronomer Imke de Pater, professor of astronomy at UC Berkeley. “These images will put some constraints on the altitude of Red Spot Jr.”

The Great Red Spot is thought to tower about 8 kilometers (5 miles) above the surrounding cloud deck. The fact that Red Spot Jr. turned red may indicate its swirling storm clouds are rising higher also, though apparently they are not as high as those of its larger companion, or the clouds are thinner.

Why the spots are red is a subject of great debate. Some people think the hurricane-like winds in the Great Red Spot, which can reach 400 miles per hour, dredge up material from deeper in the planet’s atmosphere that, when exposed to ultraviolet light, turns red. One candidate is phosphine gas, PH3, which has been detected on Jupiter. Ultraviolet light might catalyze its conversion to red phosphorus, P4, according to one of the leading theories. Other, more complicated theories have phosphine interacting in the atmosphere with chemicals such as methane or ammonia to form complex compounds such as methylphosphane or phosphaethyne.

Recent studies suggest that the red color also may be attributed to sulfur allotropes, that is, different molecular configurations, including chains and rings, of pure sulfur, such as S3-S20. The new work hypothesizes that ammonium hydrosulfide particles are carried upwards in the Great Red Spot and are broken up by ultraviolet light. Subsequent chemical reactions ultimately lead to long-chained sulfur allotropes , which can vary in color from red to yellow.

“The jury is still out on the exact processes that lead to the red coloration of the Great Red Spot – and Oval BA,” de Pater is quoted as saying in the August 2006 issue of Sky & Telescope magazine.

Christopher Go, an amateur astronomer who first noticed the coloration change of Red Spot Jr., joined de Pater’s team earlier this year. He noted that during the close encounter between the two spots, Red Spot Jr. was squashed slightly, stretching in its direction of motion. The same thing happened in 2002 and 2004 when the Great Red Spot and Red Spot Jr. passed one another, though then Junior was white.

The Great Red Spot rotates westward, opposite to the eastward rotation of the planet. Because alternating bands on the Jovian surface move in opposite directions, the adjacent Red Spot Jr. moves eastward. The planet rotates about once every 10 hours.

Another of de Pater’s colleagues, UC Berkeley mechanical engineering professor Philip Marcus, predicted several years ago that Jupiter’s climate was changing, based on the disappearance of the cyclonic storms or spots within the bands. The mixing of the atmosphere by these cyclones keeps the temperature about the same over the entire planet, he argued, so loss of this mixing will cause the equator to heat up and the poles to cool.

Earlier this year, on April 16, de Pater and her team captured near-infrared, ultraviolet and visible light photos of the planet using the Hubble Space Telescope to look more closely at the two red spots. The observations with the Keck Telescope were a follow-up study to try to measure the speeds of the swirling winds in the spots. Jupiter’s brightness, however, confused the adaptive optics system, forcing the astronomers to miss some good shots of the planet as the guide star was being positioned optimally relative to Jupiter.

“This was probably the most challenging observation ever tried with the AO system at Keck,” said de Pater, referring to use of the laser guide star system next to an object as bright as Jupiter. Adaptive optics can take the twinkle out of an object caused by thermal motion in the atmosphere, but to do this well, the target must be near another bright object that can serve as a reference. For some of the images, Jupiter’s moon Io was used as the reference “star.” But until Io got close enough for this, a laser guide star was created near Jupiter to serve this purpose.

“This was our first attempt using the laser to obtain AO-corrected images of Jupiter’s surface,” said Dr. Al Conrad, a support astronomer at the Keck Observatory. “The technique shows promise and, if we perfect it, will provide us with many more opportunities to observe this fascinating, ever-changing object.”

The team also obtained a close-up of the two spots through a narrow-band filter centered on 5 microns, which samples thermal radiation from deep in the cloud layer. Both spots appear dark because the clouds completely block heat emanating from lower elevations, though narrow regions around the spots that are devoid of clouds show leakage of this heat out into space.

“These 5 micron images reveal details in the cloud opacity not seen at the other wavelengths and will help unravel the vertical structure of the spots,” UC Berkeley team member Michael Wong added. “The smooth, narrow arcs visible to the south of each spot probably result from the interaction between the spots and high-speed winds that are deflected around them.”

The resolution using both the narrow and wide views on the camera was about 0.1 arcseconds, or only half as good as can be obtained on a clear night with optimal seeing.

The Keck observing support team included Conrad, Terry Stickel, David Le Mignant and Marcos van Dam

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea on the island of Hawaii and is managed by the California Association for Research in Astronomy, a non-profit corporation whose board of directors includes representatives from Caltech, the University of California and NASA. For more information, please visit http://www.keckobservatory.org.

Detailed Caption:

[Left]: A false-color composite near-infrared image of Jupiter and its moon Io, taken July 20 Hawaii time (July 21 UT) by the Keck II telescope on Mauna Kea using adaptive optics (AO) to sharpen the image.

Images taken in narrow band filters centered at 1.29 and 1.58 microns (shown in gold in this image) detect sunlight reflected off Jupiter’s upper cloud deck—the same clouds that are seen in visible light. The narrow band image at 1.65 micron (shown in blue) shows sunlight reflected back from hazes lying just above these clouds. The image was sharpened using the RegiStax software, developed by Cor Berrevoets. The fact that Io looks larger in the blue than in the other colors is an artefact of the image processing. Because Jupiter is much less bright in the methane band (1.65 filter), it had to be brightened relative to the other colors, which increased Io’s apparent size.

The planet Jupiter is 143,000 km (90,000 miles) across. The Great Red Spot is about twice the diameter of Earth, while Red Spot Jr. has a diameter nearly equal to that of Earth. Resolution is about 0.1 arcseconds, or 370 kilometers (250 miles). The AO system used the satellite Io as its reference star. Io itself is visible in the upper right corner in the green, red and blue colors of the 1.29, 1.58 and 1.65 micron filters, respectively. The motion of the satellite with respect to Jupiter during the observing sequence is clearly seen.

Red Spot Jr., which is below the Great Red Spot, is not as bright, either because its clouds are less dense and thus reflect less light, or because the tops of the clouds are not as high as those of the larger spot. The red outline shows the approximate area covered by the 5-micron band mosaic shown on the right.

[Right]: A closeup of the two red spots through a 5-micron filter, which samples thermal radiation from deep in the cloud layer. Both spots appear dark because the clouds completely block heat emanating from lower elevations, though narrow regions around the spots that are devoid of clouds show leakage of heat into space. This 5-micron mosaic image reveals details in the cloud opacity not seen at the other wavelengths, and will help unravel the vertical structure of the spots.

Three-telescope interferometer shows patchy red giants are common fate of stars like Sun

Kamuela, Hawaii (July 18th, 2006) - As astronomers increasingly link two telescopes as interferometers to reveal greater detail of distant stars, a Keck Observatory astronomer is showing the power of linking three or even more telescopes together.

Astronomer Sam Ragland used Arizona’s Infrared-Optical Telescope Array (IOTA) of three linked telescopes to obtain unprecedented detail of old red giant stars that represent the eventual fate of the Sun.

Surprisingly, he found that nearly a third of the red giants he surveyed were not uniformly bright across their face, but were patchy, perhaps indicating large spots or clouds analogous to sunspots, shock waves generated by pulsating envelopes, or even planets.

“The typical belief is that stars have to be symmetric gas balls,” said Ragland, an interferometer specialist. “But 30 percent of these red giants showed asymmetry, which has implications for the last stages of stellar evolution, when stars like the Sun are evolving into planetary nebulae.”

The results obtained by Ragland and his colleagues also prove the feasibility of linking a trio – or even quintet or sextet – of infrared telescopes to get higher resolution images in the near-infrared than has been possible before.

“With more than two telescopes, you can explore a totally different kind of science than could be done with two telescopes,” he said.

“It’s a big step to go from two telescopes to three,” added theoretician Lee Anne Willson, a coauthor of the study and a professor of physics and astronomy at Iowa State University in Ames. “With three telescopes you can tell not only how big the star is, but whether it’s symmetric or asymmetric. With even more telescopes, you can start to turn that into a picture.”

Ragland, Willson and their colleagues at institutions in the United States and France, including NASA, reported their observations and conclusions in a paper recently accepted by The Astrophysical Journal.

Ironically, the IOTA telescope array, operated jointly on Mt. Hopkins by the Smithsonian Astrophysical Observatory, Harvard University, the University of Massachusetts, the University of Wyoming, and the Massachusetts Institute of Technology’s Lincoln Laboratory, was shut down July 1 to save money. The initial two-telescope interferometer went online in 1993, and the addition of a third 45-centimeter telescope in 2000 created the first optical and infrared interferometer trio.

IOTA director Wesley A. Traub, formerly of the Harvard-Smithsonian Center for Astrophysics (CfA) and now at the Jet Propulsion Laboratory, offered Ragland and his colleagues the opportunity to use the array to test the limits of multiple-telescope interferometry, and perhaps learn something about the ultimate fate of the Sun.

Interferometers combine light from two or more telescopes to see more detail, simulating the resolution of a telescope as big as the distance between the telescopes. While radio astronomers have used arrays for years to simulate much larger telescopes, they have the advantage of relatively long wavelengths – meters or centimeters – which makes it easier to detect fractional wavelength differences between the arrival times of light at separated telescopes. Doing interferometry in the near-infrared – at a wavelength of 1.65 microns, or about a hundredth of a millimeter, as Ragland did – is much harder because the wavelengths are nearly a millionth that of radio waves.

“At short wavelengths, the stability of the instrument is a major constraint,” Ragland said. “Even a vibration will totally destroy the measurement.”

The astronomers also employed a new technology to combine the light from the three IOTA telescopes: a half-inch wide solid-state chip, called the integrated-optics beam-combiner (IONIC), developed in France. This contrasts with the typical interferometer, which consists of many mirrors to direct the light from multiple telescopes to a common detector.

Ragland’s main focus is low- to medium-mass stars – ranging from three-quarters the mass of the Sun to three times the mass of the Sun – as they approach the ends of their lives. These are stars that ballooned into red giants several billion years earlier, when they began burning the helium that had accumulated during a lifetime of hydrogen burning. By the end, though, these stars consist of a dense core of carbon and oxygen surrounded by a shell where hydrogen is converted to helium, and then helium into carbon and oxygen. In most of these stars, hydrogen and helium alternate as fuels, causing the brightness of the star to vary over a 100,000-year period as the fuel changes. In many cases, the stars spend their final 200,000 years as a Mira variable – a type of star whose light varies regularly in brightness over a period of 80 to 1000 days. They are named for the prototype star in the constellation of Cetus known as Mira.

“One reason I’m interested in this is that our Sun is going to take this path at some point, 4 billion years from now,” Ragland said.

It’s during this period that these stars begin to blow off their outer layers in a “superwind,” which will eventually leave behind a white dwarf at the center of an expanding planetary nebula. Willson models the mechanisms by which these end-stage stars lose their mass, primarily though strong stellar winds.

During these waning eons, the stars also pulsate on the order of months to years, as the outer layers belch outward like a release valve, Willson said. Many of these so-called asymptotic giant branch stars are Mira variables, which vary regularly as molecules form and create a translucent or nearly opaque cocoon around the star part of the time. While some of these stars have been shown to be non-circular, any asymmetric features, such as patchy brightness, are impossible to detect with a two-telescope interferometer, Ragland said.

Ragland and his colleagues observed with IOTA a total of 35 Mira variables, 18 semi-regular variables and 3 irregular variables, all within about 1,300 light years of Earth, in our Milky Way Galaxy. Twelve of the Mira variables proved to have asymmetric brightnesses, while only three of the semi-regulars and one of the irregulars showed this patchiness.

The cause of this patchy brightness is unclear, Ragland said. Modeling by Willson has shown that a companion, such as a planet in an orbit similar to Jupiter’s orbit in our own system, could generate a wake in the stellar wind that would show up as an asymmetry. Even a closer Earth-like planet could generate a detectable wake if the stellar wind was strong enough, though a planet too close to the expanded envelope would quickly be dragged inward and vaporized by the star.

Alternatively, large amounts of material expelled from the star could condense into clouds that block some or all of the light from part of the star.

Whatever the cause, Willson said, “this is telling us is that the assumption that stars are uniformly bright is wrong. We may need to develop a new generation of three-dimensional models.”

“This study, the largest ever of this class of late-type stars, is the first to demonstrate the degree to which late type-stars, especially the Mira variables and carbon stars, show the effects of hot and cold spots,” said coauthor William Danchi of NASA Goddard Space Flight Center. “This has implications for how we interpret observations when we use infrared interferometers to search for planets around red giants.”

Ragland’s coauthors are Traub; Jean-Pierre Berger, P. Kern and F. Malbet of the Laboratoire d’Astrophysique de Grenoble (LAOG) in France; Danchi; J. D. Monnier and E. Pedretti of the University of Michigan, Ann Arbor; Willson; N. P. Carleton, M. G. Lacasse and M. Pearlman of CfA; R. Millan-Gabet of the California Institute of Technology; F. P. Schloerb, M. Brewer, K. Perraut, K. Souccar and G. Wallace of the University of Massachusetts, Amherst; W. D. Cotton of the National Radio Astronomy Observatory in Virginia; Charles H. Townes of the University of California, Berkeley; P. Haguenauer of ALCATEL Space Industries of Cannes, France; and P. Labeye of the Laboratoire d’Electronique de Technologie de l’Information (LETI) in Grenoble, which is part of the French Atomic Energy Commission (CEA). The IONIC chip was developed jointly by LAOG, the Institut de Microélectronique, Électromagnétisme et Photonique (IMEP) and LETI.

The work was supported by NASA through a Michelson Postdoctoral Fellowship and by the National Science Foundation.

The W. M. Keck Observatory is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA. The observatory was made possible by the generous financial support of the W. M. Keck Foundation.

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The paper, “First Surface-resolved results with the IOTA imaging interferometer: detection of asymmetries in AGB stars,” is available for download at http://arxiv.org/PS_cache/astro-ph/pdf/0607/0607156.pdf.

Keck Observatory video wins 2006 Telly Award for excellence in video production

Kamuela, Hawaii (July 12th, 2006) - An educational video produced by the W. M. Keck Observatory and the production company Earlybird & Friends has won a Silver Telly Award, the highest of the Telly Awards given annually to honor outstanding local, regional and cable TV programs, films and commercials.

The video, titled “The Kecks of Mauna Kea,” was produced last year by the California Association for Research in Astronomy, the organization that operates the Keck Observatory, and the Redmond, Wash. production company, which specializes in video and multimedia storytelling. The winning video is about the observatory’s mission to expand the frontiers of astronomy by building for scientists the world’s two largest optical telescopes, now sitting side by side atop the dormant Mauna Kea volcano on the island of Hawaii.

“We are most pleased to have received a Telly Award for ‘The Kecks of Mauna Kea.’ It vividly captures the extraordinary story of the building of the world’s two largest telescopes and of some of their amazing early discoveries,” said Dr. Frederic H. Chaffee, Director Emeritus of the Keck Observatory.

Earlybird & Friends also won a Telly Award last year for their PBS Hawaii production, “First Light,” about the controversy surrounding the placement of telescopes atop Mauna Kea, a sacred mountain for native Hawaiians.

“I always got a charge of excitement when the Keck telescopes went into action,” said Roland Yamamoto of Earlybird, who directed and wrote “The Kecks of Mauna Kea” along with producer and writer Laura (Kraft) Kinoshita of Keck.

“We always kept in mind that astronomy buffs and science students would love to be where we were, and see what we saw inside the Keck Observatory. So we did our best to create a window for them, into one of world’s most incredible scientific tools.”

Recipients of the 27th annual Telly Awards, announced June 23, were selected from more then 13,000 submissions in 163 commercial and 128 film and video categories, representing all 50 states and numerous foreign countries. Fewer than 10 percent of entrants receive a silver medal, the highest honor; fewer than a quarter receive a bronze. All entries are judged independently, not in competition with one another.

The Telly Awards were established in 1979, each year’s winners representing the best work of the top advertising agencies, production companies, television stations, cable operators and corporate video departments in the world.

For more information on the Telly Awards, link to http://www.tellyawards.com.

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Contact:
Frederic Chaffee, Observatory Director Emeritus, .(JavaScript must be enabled to view this email address), (808) 885-7887
W. M. Keck Observatory
California Association for Research in Astronomy
Kamuela, HI 96743
http://www.keckobservatory.org

NSF Partnership Funds Instrument for World’s Largest Telescope

Kamuela, Hawaii (May 25th, 2006) The W. M. Keck Observatory and the National Science Foundation (NSF) announced that $5 million of NSF funding has been granted over the next four years to design and construct a major new capability for the Keck I telescope. It was also announced that a matching gift of $5 million from philanthropists Gordon and Betty Moore has been received to complete full funding for the project to build an infrared, multi-object spectrograph to measure phenomena at the farthest reaches of the universe. The spectrograph will be operational by late 2009.

The new instrument, known as the Multi-Object Spectrograph for InfraRed Exploration (MOSFIRE), is being developed through a collaborative team of scientists and engineers representing the Keck Observatory, University of California at Los Angeles, California Institute of Technology, and University of California at Santa Cruz. When operational, MOSFIRE will allow astronomers to study the first generation of galaxies formed shortly after the Big Bang 13.7 billion years ago. By simultaneously measuring up to forty infrared spectra, or cosmic “fingerprints,” of distant galaxies, the instrument will be capable of undertaking ambitious sky surveys in a fraction of the time currently possible, surveys currently far too time consuming to even consider with today’s technology.

“At a time in our nation’s history when public funding for basic research is far less than it needs to be to keep us competitive, it is especially encouraging that concerned private citizens are stepping forward,” said Dr. Frederic H. Chaffee, director of the W. M. Keck Observatory. “The generosity of Gordon and Betty Moore will not only lead to many unexpected discoveries that may very likely transform our understanding of the early universe, it will also support our nation’s continued leadership in science, technology and innovation.” Moore is the co-founder and long-time CEO of Intel.

The NSF funding for MOSFIRE was provided under the Telescope System Instrumentation Program (TSIP) which aims to provide access for U.S. astronomers to privately funded observatories such as Keck through a competitive application process. In exchange for funding for new instrumental capabilities under TSIP, observing time is made available to any U.S. astronomer whose project is approved by a panel of peers.

“Our past funding of instruments at Keck has enabled just the kind of ‘system’ of observatory collaborations that we envisaged when the TSIP program was inaugurated in 2002,” said Dr. Todd Boroson, deputy director of the National Optical Astronomy Observatories in Tucson, AZ, which administers the TSIP program for NSF. “Astronomers who would otherwise not have access to the world’s largest telescopes have benefited greatly from this program and have made U.S. astronomy much stronger as a whole.”

Dr. Wayne van Citters, director of the Division of Astronomical Sciences at the NSF, echoed these sentiments: “NSF Astronomy is the federal agency responsible for the stewardship of all ground-based astronomy at a time when other nations are challenging the leadership role in astronomical research that the United States has held for over a century. Programs like TSIP are aimed at leveraging all our scientific capabilities, both publicly or privately funded, and, by every measure, this still-young program has been very successful.”

The W. M. Keck Observatory operates twin 10-meter telescopes located on the summit of Mauna Kea on the island of Hawai’i and is managed by the California Association for Research in Astronomy, a non-profit 501 (c) (3) corporation whose board of directors includes representatives from Caltech, the University of California and NASA.

Taft E. Armandroff Appointed Director for W. M. Keck Observatory

Kamuela (February 2nd, 2006) The Board of the California Association for Research in Astronomy (CARA), the governing body for the W. M. Keck Observatory, is pleased to announce that Dr. Taft E. Armandroff has been appointed director of the Observatory, effective July 1, 2006. He will succeed Dr. Frederic H. Chaffee, who will end his second 5-year term as Director on June 30th.

“The CARA Board is very pleased that Taft Armandroff has accepted this position,” said Dr. C. Judson King, chairman of the CARA Board. “Dr. Armandroff has demonstrated a clear understanding of the unique opportunities available to Keck and possesses the vision and insight to move the Observatory forward in the years ahead.”

Armandroff is associate director at the National Optical Astronomical Observatory (NOAO) in Tucson, Ariz. He is also director of the Gemini Science Center at NOAO where he is responsible for having developed robust user support for U.S. users of the Gemini North and South telescopes, as well as overseeing the construction of several powerful instruments for them. “Dr. Armandroff’s experience in both of these areas will be of enormous value to the Keck Observatory and its users,” said King.

In accepting this appointment, Armandroff said “It is truly an honor and a privilege to be asked to lead such a dynamic and accomplished organization as the W.M. Keck Observatory. I am eager to work with its staff, the CARA Board and the community of Keck astronomers to keep Keck at the forefront of scientific discovery.”

Armandroff, who is a widely recognized research astronomer in the fields of dwarf spheroidal galaxies, globular clusters, and dark matter, also has significant ties to Hawaii through his work with the Gemini Observatory in Hilo. His appointment will help continue the working collaboration between the Keck and Gemini Observatories to improve scientific capabilities at Mauna Kea, while respecting the mountain’s distinctive environmental and cultural resources.

The present Keck Director Dr. Frederic Chaffee will be stepping down after ten years at the helm of the Observatory. “When I accepted this extraordinary position in 1996, I made it clear to the Board that I would be the Director for no more than a decade. A great, young, world-class research facility like the Keck Observatory thrives on innovation and new ideas. It is always healthy to bring in fresh ideas in top level management as well, and I’m thrilled that an astronomer of Dr. Armandroff’s caliber will lead Keck toward its even brighter future. For myself, I intend to remain in Hawaii and contribute in any way I can to astronomy’s future here, the best place on the planet for astronomical research. My decade at Keck has been the highlight of my long and fulfilling career in astronomy.”

During his tenure, Chaffee’s leadership nurtured the development and implementation of the adaptive optics science program at the Keck Observatory. The field of adaptive optics is considered by many to be the most important technological breakthrough in astronomy since the invention of the telescope more than 400 years ago. Chaffee also worked closely with NASA and the Jet Propulsion Laboratory to develop the Keck Interferometer, an instrument that combines the infrared light of both Keck telescopes for large improvements in resolving power. The Keck Interferometer is now being used to search for large planets orbiting stars other than the Sun.

CARA Board Chairman King said, “Fred Chaffee is the reason the Keck Observatory has reached its enormous international stature. We are considerably in his debt for all that he has done, and we are delighted that he will remain in Waimea and contribute further.”

The W. M. Keck Observatory is managed by the California Association for Research in Astronomy, a non-profit 501 (c) (3) corporation whose board of directors includes representatives from Caltech, the University of California and NASA.

Trojan Asteroid Patroclus: Comet in Disguise?

Mauna Kea (February 1st, 2006) Like the hollow wooden horse hiding Greek warriors in the Trojan War, could an entire population of asteroids be masquerading as comets? Observations of the binary Trojan asteroid (617) Patroclus taken at the W. M. Keck Observatory on Mauna Kea have astronomers wondering if asteroids caught in the gravitationally neutral zone of the Sun-Jupiter system might actually be ancient comets and space dust.

Dr. Franck Marchis of the University of California at Berkeley is leading an international team of astronomers that has discovered that the composition and density of the Patroclus system is remarkably similar to that of comets. The components are less dense than water, probably porous and probably, like snow, made out of water ice. The results, published in the February 2nd issue of Nature, are raising important questions about how this Trojan asteroid migrated to its current location in the solar system and it how it acquired its binary nature.

Trojan asteroids are those that lie 60 degrees in front or 60 degrees behind the planet Jupiter in its orbit around the Sun. They are relatively small and quite faint, making them difficult to study even with the world’s largest ground-based telescopes. A new technique using sodium lasers with ground-based image-correcting technology called “Laser Guide Star Adaptive Optics” (LGS-AO) is helping scientists study asteroids with more detail than ever before.

The LGS-AO system installed on the Keck II 10-meter telescope at Mauna Kea removes the blurring effects caused by Earth’s atmosphere from astronomical images and produces the finest infrared images in the world.

“Space telescopes are tremendous tools for observing remote solar system targets, but large ground-based telescopes equipped with Laser Guide Star Adaptive Optics systems provide both the power to collect more light and the ability to study objects with even more detail,” said Dr. David Le Mignant, adaptive optics scientist and lead team member for the LGS-AO science operations at the W. M. Keck Observatory. “With LGS-AO, we observe a different population of solar system targets: fainter and smaller objects like Patroclus and more distant ones like the object beyond Pluto. This should lead us to many new discoveries,” added Dr. Le Mignant.

Modern theories suggest that Trojan asteroids may have formed in the Solar Nebula at the same time as the rest of the solid bodies in the Solar System. To date, more than one thousand such asteroids have been discovered.

Asteroid Patroclus was previously believed to be a single object about 150 kilometers (90 miles) in diameter, but recent observations from the Gemini North telescope in Hawaii found that Patroclus is actually comprised of two objects, making it the first binary Trojan asteroid to be discovered. The discovery of a binary asteroid was not as surprising as the fact that the two objects are nearly identical in size. Dr. Marchis’ team found the larger piece is 122 kilometer (76 miles) wide at its largest point, and the similar-sized partner is 112 kilometers (70 miles). The two pieces orbit their center of mass every four days, separated by a distance of about 680 kilometers (423 miles). The names of these objects are associated with the heroes of Homer’s Iliad. The asteroid Patroclus was named after the best friend and companion to Achilles, the main character of the story and Greek hero of the Trojan War.

Scientists believe there may be as many Trojan asteroids as there are main-belt asteroids, but they are difficult to study with high spatial resolution because they are too faint for most adaptive optics systems.

“The Laser Guide Star system is a remarkable breakthrough in ground-based observations,” said Dr. Franck Marchis of the University of California at Berkeley. “With such a capability we are able to regularly study small bodies in the solar system in ways that were not possible before. We want to thank the Keck Observatory Adaptive Optics team for their involvement in our observing program which helped make these results possible.”

Since collisions of small bodies in the solar system typically happen at relatively high speeds and leave behind lots of small debris, it is unlikely that Patroclus was formed this way, or that an asteroid the size of Patroclus would have experienced a collision in the last billion years. How then, could the Patroclus binary system have formed?

New results have some scientists theorizing that Patroclus originated from a very early time in the solar system’s history, about four and a half billion years ago. Patroclus may have formed during the accretion phase of solar system formation, similar to thousands of other objects in the Kuiper Belt, an outer region of the solar system beyond the orbit of Neptune. Recent simulations suggest that the giant gas planets migrated outward and gravitationally removed neighboring planetesimals. Some of these objects were then subsequently caught into the gravitationally-stable Lagrangian points of the Jupiter-Sun system.

The story of Patroclus may be even more complex: As Patroclus encountered the planet Jupiter several billion years ago, it may have gotten a little too close to the mighty planet. The tremendous gravitational forces of Jupiter, which are three times stronger than that of Earth, may have split the small and porous body in half through an effect known as “tidal splitting.”

“The Patroclus system displays similar characteristics to binary Near-Earth asteroids,” said Dr. Marchis. “Near-Earth binary asteroids are believed to be formed during an encounter with a planet, which results in tidal splitting. Recent published work from our collaborators leads us to suggest that a Trojan asteroid may be formed in a similar way—through an encounter with Jupiter. This scenario is different than what is believed to cause binary asteroid systems in the main asteroid belt, which typically feature two or more bodies of unequal size.”

The team responsible for finding the mass and size of the Trojan binary asteroid Patroclus are Franck Marchis, Imke de Pater and Michael H. Wong of the University of California at Berkeley; Daniel Hestroffer, Pascal Descamps, Jérôme Berthier and Frédéric Vachier of the Institut de Mécanique Céléste et de Calcul des Ephémérides (IMCCE); and Antonin Bouchez, Randall Campbell, Jason Chin, Marcos van Dam, Scott Hartman, Erik Johansson, Robert Lafon, David Le Mignant, Paul Stomski, Doug Summers and Peter Wizinowich of the W. M. Keck Observatory.

Funding for the project was provided by the National Science Foundation Science and Technology Center for Adaptive Optics and by the National Aeronautics and Space Administration (NASA) through the Science Mission Directorate Research and Analysis Programs.

Data was obtained between November 2004 and May 2005 with the second generation Near Infrared Camera (NIRC2) on the Keck II 10-meter telescope at the W. M. Keck Observatory, managed by the California Association for Research in Astronomy, a non-profit 501 (c) (3) corporation. The first Keck telescope began observations in May, 1993. Its twin joined in 1996. Together, the telescopes are the world’s most powerful eyes looking into the optical and infrared universe.

Spend The Summer Among the Stars: Internships Available at Observatories on Mauna Kea

Kamuela (January 20th, 2006) The Akamai Observatory Internship Program offers remarkable opportunities to participate in the exciting world of modern astronomy via paid summer internships at Observatories on Mauna Kea. The Akamai program pairs undergraduate university and community college students with engineers and astronomers at Hawaii Island observatories for eight-week project-based internships.

The program begins with a week long short course which offers students the big picture view of what modern astronomy and observatories are all about. Plenty of fun and hands-on activities are built into the experience, along with a chance to get to know the rest of the class before each student starts their internship at one of the observatories on Mauna Kea.

Last summer eleven students worked at five different observatories (Gemini, Keck, Subaru, Smithsonian Submillimeter and the University of Hawaii’s Institute for Astronomy) on projects that ranged from two-way radio maintenance to installing Web-based weather surveillance cameras on the summit, to creating a computer program to graphically display asteroid data. The program is designed for students interested in science, engineering or technology and preference is given to those with ties to Hawaii.

Pearl Yamaguchi, a senior at University of Hawaii at Manoa in electrical engineering, worked with Steve Colley, an electrical engineer at Subaru Telescope. Of her experience she said, “It was very real life, and I got a real different sense of what the actual work [of electrical engineering] is like.” She also found the work challenging adding, “which is good, because it’s definitely not boring.”

Blake Stene, an electronics technology student from Hawaii Community College, worked at the Keck Observatory and said, “I couldn’t have paid for this experience; I got paid to learn stuff….pretty cool!”

Kaniela Dement, a junior at UH Hilo majoring in astronomy, worked with Optical Engineer Celine D’Orgeville at the Gemini North Observatory on their laser guide star system. Referring to the technical work he said, “this experience gave me a better understanding of lasers, the science behind them and why they’re needed.” On the organizational level he noticed, “from the custodian to the senior astronomer, everyone plays an active role in furthering mankind’s knowledge of the heavens.”

When asked to rate their overall experience at their internship site all eleven students indicated they were “extremely satisfied.” Additionally 73 percent reported that the experience changed the way they were thinking about, or planning, their education or career and 82 percent reported that the program will be very influential in how they proceed with their education and career.

The program is sponsored by the Center for Adaptive Optics (CfAO), a National Science Foundation Science and Technology Center in collaboration with the observatories on Mauna Kea and educational institutions in Hawaii to develop pathways for local students into astronomy and observatory work. Another purpose of the program is to encourage education collaboration among the Observatories at Mauna Kea, as well to assist in the development of a Hawaii-based technology workforce.

The CfAO also collaborates with high tech businesses, Maui Community College and The Maui Economic Development Board to coordinate a similar internship program on Maui, placing students with Maui high tech businesses. This program is also available to undergraduate university and community college students.

This summer’s Hawaii Island program will run from June 5th through the end of July. The program will conclude with a public symposium where each student will present a short talk on his or her project. During the internships the students meet weekly via video and telephone conferencing from their work sites to discuss their experiences and work with CfAO staff on their final presentations as well as resumes, career planning and other work-related skills. The deadline to be considered for internships this coming summer is February 14th.

Contact Sarah Anderson at (808) 881-3839 for more information on both programs. The online application is at: http://cfao.ucolick.org/EO/internshipsnew.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose board of directors includes representatives from the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration.

`OHANA to Link Seven Mauna Kea Telescopes

Mauna Kea (January 13th, 2006) A team of scientists in partnership with the W. M. Keck Observatory in Hawaii have successfully passed the first test in a project that will link the seven largest telescopes on Mauna Kea together to create a gigantic imaging instrument nearly one half mile (800 meters) in diameter. The ‘OHANA (Optical Hawaiian Array for Nanoradian Astronomy) array, or “interferometer,” will provide ultra-high resolution images of the near-infrared universe, 80 times more accurate than a single 10-meter Keck telescope. The results of the first successful test between the two Keck telescopes are described in the January 13th issue of Science.

An interferometer is a type of instrument that combines light from two or more telescopes to obtain measurements with higher resolution than what could be obtained with a single telescope alone. With conventional telescopes, the size of a single, primary mirror will determine its ability to resolve small-scale structure on the sky. But with an interferometer, the distance between the telescopes, or “baseline,” will determine the angular resolution.

“The next large telescopes will certainly be 30 to 50 meters in diameter, when some of the answers we are looking for would require mile-long diameters. Only interferometers can achieve this; and the Mauna Kea summit is the only place where we can find large optical telescopes spread over such distances,” said Dr. Fred Chaffee, director of the W. M. Keck Observatory.

The `OHANA project, named after the Hawaiian word for family and extended family, will eventually link the Subaru Telescope, NASA Infrared Telescope, Gemini Observatory, Canada-France-Hawaii Telescope, the United Kingdom Infrared Telescope Facility and the Keck I and Keck II telescopes together with “single-mode” optical fibers never used before to transport the light between telescopes.

“The use of fibers to transport the light between telescopes is one of the main challenges of the `OHANA project,” said Dr. Olivier Lai, resident astronomer at the Canada-France-Hawaii Telescope.

When complete, ‘OHANA will be the most highest-resolution, near-infrared instrument in the world—capable of producing images with an unprecedented resolution of 0.5 milliarcseconds, about the size of an edge of paper as seen from one hundred miles away. It will be used to take detailed images of stellar surfaces, giant gas planets, long-period variable stars and significantly advance the understanding of stellar astrophysics.

Modern interferometers typically have baselines a few hundred yards in distance. Increasing the distance (and its corresponding resolving power) usually requires a large number of mirrors, each of which deteriorates the quality of light arriving at the detector for measurement. A solution to this problem may be single-mode optical fibers which transmit light only at a particular wavelength of interest and significantly reduce the loss of light over large distances. The first experiment of the `OHANA project was to test the effectiveness of these types of fibers and to determine the feasibility of using them with long baseline optical interferometers.

The first `OHANA test was conducted on June 17 with the Keck I and Keck II telescopes. Both telescopes guided on a relatively bright star (107 Hercules), located 278 light years away. The single-mode fibers were used to transmit the infrared light over a simulated baseline of ~550 yards (~500 meters), which was then coherently combined and successfully measured. The experiment was the first major milestone for the future of very large optical arrays connected with optical fibers.

“This first success is not only important for `OHANA but also a major milestone towards future kilometric arrays of telescopes in the near infrared,” said Dr. Guy Perrin, astronomer at Paris Observatory.

Future tests will link the Canada-France-Hawaii Telescope with the Gemini North telescope, followed by other baselines such as Subaru Telescope to W. M. Keck Observatory for example. The goal of each test is to characterize the baseline between telescopes before completing the entire Mauna Kea array.

A unique aspect of the `OHANA project is its non-invasive approach for expanding the capabilities of the existing facilities at Mauna Kea. In response to community concerns, many scientists at Mauna Kea are seeking ways to efficiently use the existing world-class telescopes in creative new ways. The `OHANA project will not require the construction of any new permanent facilities, and the very thin optical fibers used to connect the telescopes can be installed using the existing roads and infrastructure of the Astronomy Precinct.

“OHANA demonstrates the spirit of cooperation between the observatories on Mauna Kea to make the best use of the existing research resources whenever possible,” said Dr. Rolf Kudritzski, director for the Institute for Astronomy at the University of Hawaii, which manages the astronomy research program at Mauna Kea. “The ‘OHANA Project uses the best of what we have to combine the power of the largest telescopes in the world to create a unique new astronomical facility of unprecedented capability. This is a milestone for the future of astronomy on Mauna Kea.”

The ‘OHANA project is led by Paris Observatory in collaboration among Canada-France-Hawaii Telescope Corporation, W.M. Keck Observatory, the National Astronomical Observatory of Japan, Gemini Observatory, United Kingdom Infrared Telescope, NASA Infrared Telescope Facility, the Institute for Astronomy at the University of Hawaii, the National Optical Astronomical Observatory, the, Institut National de Rercherche en Communication Optique et Micro-Ondes and Institut National des Sciences de l’Univers du CNRS.

The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose board of directors includes representatives from the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration.

Scientists See Better, Fainter with New Keck Laser Guide Star

Washington D. C. (January 10th, 2006) A new sodium laser is giving 50 times more sky coverage to the atmospheric-correcting technology known as adaptive optics on the Keck II telescope at Mauna Kea, Hawaii. The laser lets scientists explore most of the sky with adaptive optics and gives them the capability to study objects that were previously too faint to be seen with the system. Since 1999, Keck Adaptive Optics has provided 10 times more resolving power than what could otherwise be achieved from the ground. The results are producing infrared images from the ground comparable – and often better – than those taken from space.

“This has been the most exciting technological and scientific breakthrough for the Observatory in the last decade. It may forever change the way we do astronomy from the ground,” said W. M. Keck Observatory Director Fred Chaffee. “We are entering a new, extraordinary era of discovery.”

After just one year of regular scientific use, the Keck Laser Guide Star Adaptive Optics system is producing spectacular results and advancing research in several fields of astronomical study. Findings include the discovery of new asteroids, moons and planetoids in our solar system, the detection of new brown dwarf binary systems—including a strange new kind of binary, observations of physical processes taking place near a supermassive black hole, and new findings about extremely distant supernovae and young galaxies.

The technique of adaptive optics uses visible light from a bright star to measure and correct for atmospheric distortions at infrared wavelengths. But only about two percent of the sky has stars bright enough to use with adaptive optics. The Keck Laser Guide Star system overcomes this limitation by creating an artificial star anywhere in the sky. The W. M. Keck Observatory is the only 8 10 meter class facility in the world currently providing this capability to observers.

“The wish list for astronomers is pretty simple,” said Dr. David Le Mignant, adaptive optics scientist at the W. M. Keck Observatory. “First, they want the highest-quality images that can possibly be obtained. Second, they want to look anywhere they want to in the sky. The laser guide star makes both these wishes come true.”

Operating at nearly 1,000 times a second, the Keck adaptive optics system minimizes the blurring effects of Earth’s atmosphere to provide infrared images 10 times better than what can be achieved from the ground. Without any correcting technology, the best telescopes on Earth are limited to an average “seeing” ability, or resolving power, of about 0.5 arcseconds, the equivalent of being able to distinguish an object the size of a blueberry from 2.5 miles (4 km) away. But with adaptive optics, atmospheric blurring is removed, producing a resolving power of about 50 milliarcseconds or better. This improvement is like looking at a penny from 2.5 miles away and being able to read the words, “ONE CENT” and “Liberty” stamped on the coin.

“We are shattering a limitation for ground-based observations—astronomers can now uncover and study fine structures in extremely faint objects anywhere, within and beyond our galaxy, ” said Dr. Le Mignant. “This new data will particularly complement present deep sky surveys which study the formation of galaxies in the universe.”

More than 21 scientific results made possible with the Keck Laser Guide Star system are presented today at the 207th meeting of the AAS in Washington D.C. Among the many new significant findings discussed at Special Session 98, “Seeing the Universe in a New (Sodium) Light”:

* In the distant regions of our solar system, scientists at Caltech have used the Keck Laser Guide Star to discover three new satellites orbiting some of the largest objects in the Kuiper belt. The surprising properties of these moons suggest that they are formed very differently from the tiny moons known to orbit smaller Kuiper Belt Objects. (A. Bouchez, Caltech)
At the center of our own Milky Way galaxy, the hostile environment around the supermassive black hole should make it difficult for stars to form, but a group of massive young stars has been detected and their origins are puzzling scientists. The problem has been dubbed “the paradox of youth.” Now, UCLA scientists are able to measure how these young stars move across the sky with an unparalleled precision of only two kilometers per second, and determine, for the first time, the orbit of each of the young stars located more than a few light months from the black hole. Scientists are using the stars’ orbits, which retain an imprint of their origin, to understand how and where these young stars may have formed. (J. Lu, UCLA)

* Also in the Milky Way, scientists at the University of Hawaii are discovering new ultracool brown dwarf binary systems, including a strange new kind of binary never seen before. (M. Liu, UH-IfA)

* Scientists at UCSC and the Supernova Cosmology Project observed a supernova in a galaxy as it appeared when the universe was only 40 percent its current age (z=1.3). The Keck Laser Guide Star system allowed the team to study the faint system and resolve the supernovae from the galaxy core, separated by only 0.4 arcseconds. The discovery was made as part of a major, long-term project called “Center for Adaptive Optics Treasury Survey” or CATS, a project that is looking at deep Hubble galaxy fields with the Keck Laser Guide Star System. (J. Melbourne, Lick/UCSC)

“Major advances in astronomy are often the driven by having new technologies to explore the heavens,” said Michael Liu of the Institute for Astronomy at the University of Hawaii. “Through years of effort and dedication of many people, the Keck system is allowing us to see the whole of the universe in a new (sodium) light.”

More than 20 percent of all available observing nights through July 2006 on the Keck II telescope will use the sodium laser. Laser guide star systems do not outperform natural guide stars, but rather take over in the faint skies where sufficiently bright stars do not exist. With bright objects of magnitude 10 or greater, natural guide star systems still provide slightly better images, and will be used for about 30 percent of the adaptive optics research at W. M. Keck Observatory.

The Future
Regularly using sodium lasers with adaptive optics is in its early stages, but laser guide stars are being developed for most major observatories, most notably the European Southern Observatory’s Very Large Telescope, the Gemini North and Gemini South telescopes and the National Astronomical Observatory of Japan’s Subaru Telescope. Plans are also underway to install a new laser guide star system on the Keck I telescope within the next three years, and also to improve the efficiency and reliability of the existing laser system on Keck II.

Acknowledgements
The W. M. Keck Foundation provided major funding for the construction of the twin 10-meter Keck telescopes and for the adaptive optics and laser guide star systems. Additional funding for the Laser Guide Star Adaptive Optics system was provided by NASA, Lawrence Livermore National Laboratory (LLNL) and the Center for Adaptive Optics. The Laser Guide Star Adaptive Optics system was implemented by a team at W. M. Keck Observatory. The sodium laser was developed at LLNL. The W. M. Keck Observatory is managed by the California Association for Research in Astronomy, a non-profit 501 (c) (3) corporation whose board of directors includes representatives from Caltech, the University of California and NASA.

GRAIN GROWTH IN ORION NEBULA PROTOPLANETARY DISKS

WASHINGTON, D. C. (January 6th, 2006) New observations of the Orion Nebula at infrared wavelengths reveal that small dust grains located in disks around young stars are growing, taking the initial steps toward forming planets despite bathing in a flood of radiation from highly luminous stars. The properties of dust in disks around young stars plays a pivotal role in understanding star formation and determining the origins of planets in our Solar system and in extrasolar planetary systems as well. The results are presented today at the 207th meeting of the American Astronomical Society in Washington, D. C.

“One of the key questions we are trying to address is whether or not planets can form around young stars in the seemingly hostile environment of the Orion Nebula,” said Dr. Marc Kassis, support astronomer at the W. M. Keck Observatory and lead author of the poster sharing the results.

The Orion Nebula, located about 1500 light years away, is an energetic stellar nursery giving birth to thousands of young, Sun-like stars with protoplanetary disks. But a few of these newborn stars are 10 to 30 times the mass of our Sun and 10,000 times as bright. These massive stars bathe the entire region in harsh ultraviolet radiation which evaporates the protoplanetary disks of their lower mass neighbors.

“You would think that the strong ultraviolet radiation that is evaporating these disks would also inhibit planet formation, but the larger particles we see in these Orion disks seem to suggest otherwise,” said team member Dr. Nathan Smith, Hubble Fellow at the University of Colorado.

To determine the relative sizes of the grains in these protoplanetary disks, the research team used the Long Wavelength Spectrometer on the Keck I 10-meter telescope and the Mid-Infrared Spectrometer and Imager at the 3-meter NASA Infrared Telescope Facility, both situated 14,000 feet atop Mauna Kea on the island of Hawai`i.

In the optical part of the spectrum, these protoplanetary disks are dark and are sometimes viewed in silhouette against the bright nebula. In contrast, the dusty disks are extraordinarily bright in the infrared (see Fig 1). The observations revealed broad spectral signatures of silicate grains, and the overall shape of the spectra was unlike the silicate emission of relatively smaller grains typical of the interstellar medium. “The silicate profiles from the protoplanetary disks are generally flat-topped instead of peaked, indicating the grains have increased in size since the birth of these disks,” said Dr. Kassis. “You wonder whether the grains will grow enough to start forming planets.”

“Could our own solar system have formed in such an environment?” posed Dr. Ralph Shuping, support scientist for the Stratospheric Observatory for IR Astronomy (SOFIA). “Careful study of primitive materials in meteorites suggests that it was, and our observations show that the initial stages of grain growth that lead to planet formation can occur in protoplanetary disks born in Orion-like environments.”

Most stars are born in clusters with bright, massive stars relatively nearby. The stars in clusters and their protoplanetary disks born in regions like the Orion Nebula can be exposed to the intense ultraviolet radiation from massive stars, stellar winds, jets, gravitational pulls from their neighbors, and supernova explosions. Yet, recent theoretical work and the study of primitive meteorites indicate that our Solar System may have been born in a region like the Orion Nebula.

“Some years ago, we thought ultraviolet radiation would be hazardous to disks,” said Dr. John Bally at the University of Colorado. However, recent work by Drs. Henry Throop of the Southwest Research Institute and Bally showed that ultraviolet irradiation could promote the rapid formation of planets. “So, in disks where grains have grown and settled to the disk mid-plane, ultraviolet radiation can remove gas, leaving large particles behind to accumulate through their mutual gravitation into small, planet-like objects,” added Dr. Bally.

The team’s observations also hint at the composition of the grains. From details in the shape of the infrared spectra, the team is identifying the presence of silicate minerals such as olivine and fosterite; olivine being the same mineral found along the green sand beaches in Hawai`i.

“It’s amazing to think that we can study the minerology of these tiny grains 1500 light years away!” remarked Dr. Shuping.

The team responsible for the discovery of grain growth in Orion Nebula protoplanetary disks is Ralph Shuping (USRA-SOFIA), Marc Kassis (W. M. Keck Observatory), Mark Morris (UCLA), and Nathan Smith and John Bally (University of Colorado). The team acquired data at NASA’s IRTF through a collaboration with the instrument team that includes Joseph Adams (Cornell University), Joseph Hora (Harvard-Smithsonian Center for Astrophysics), James Jackson (Boston University), and Eric Tollestrup (UH-IfA, NASA IRTF).

This work was supported by the Colorado Center for Astrobiology and the UCLA Center for Astrobiology, both supported by the NASA Astrobiology Institute. The Infrared Telescope Facility is operated by the University of Hawaii under Cooperative Agreement no. NCC 5-538 with the National Aeronautics and Space Administration, Office of Space Science, Planetary Astronomy Program. Some of the observations for this research were provided by the W. M. Keck Observatory using Director’s discretionary time, also known as “Team Keck.” The W. M. Keck Observatory is operated by the California Association for Research in Astronomy (CARA), a non-profit 501 (c) (3) corporation whose board of directors includes representatives from the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration.

FAINT NEW RING DISCOVERED AROUND URANUS

BERKELEY, Calif. (December 22nd, 2005) Astronomers have made the first ground-based observations of one of two new rings discovered recently around the planet Uranus by the Hubble Space Telescope and announced today.

The ground-based detection was conducted with the Near Infrared Camera (NIRC2) using the adaptive optics system on the Keck II telescope atop the Mauna Kea volcano in Hawaii.

The new discoveries within the Uranus ring system are being made thanks to the superb instrumentation that researchers are now using on both the Keck and Hubble telescopes, and because of the current angle of Uranus’ rings as seen from Earth, according to Imke de Pater, a professor of astronomy at the University of California, Berkeley, and leader of the ring science Keck observing team.

De Pater explained that our perspective on the planet’s rings changes as Uranus and Earth orbit the sun. The rings are now “closing up” and in 2007 will appear edge-on from Earth, providing astronomers with an opportunity to see faint rings. The path lengths through the dusty rings increase as the rings close up, so that any faint rings will become progressively more visible.

De Pater, Heidi B. Hammel of the Space Science Institute in Boulder, Colo., and Seran Gibbard of Lawrence Livermore National Laboratory, announced their observations of the innermost new ring today in a circular issued by the International Astronomical Union (IAU). The initial discovery of Uranus’ two new rings was announced in the same IAU circular, issued Dec. 22, and will appear in the Dec. 23 issue of the journal Science. Authors of that report are Mark R. Showalter of the SETI Institute and Jack J. Lissauer of the NASA Ames Research Center, both located in Mountain View, Calif.

“We have been puzzled by the fact that we cannot detect the outer ring, even though it is more than twice as bright as the inner ring in the Hubble data,” de Pater said. “The difference is probably caused by the fact that we are working in the infrared, at a wavelength four times longer than that used by the Hubble telescope in the rings’ discoveries. This seems to suggest a color difference between the two rings, which would indicate that their constituent particles are very different.”

Specifically, the team concludes, the outer ring is much less red, which would suggest it is made of tinier particles. This would be consistent with the hypothesis by Showalter and Lissauer that the inner ring may have a large population of unseen source bodies, whereas the outer ring may be composed entirely of dust ejected from Uranus’ tiny moon, Mab.

“A normal dusty ring is red,” said de Pater, noting that Jupiter’s rings and Saturn’s G ring are distinctly red. Only Saturn’s E ring, nearest to the moon Enceladus, is blue.

“If a ring has a lot of tiny particles, it will be bluer, because smaller particles do not scatter efficiently in the red,” added Gibbard.

“Because our team was observing in the near infrared - an invisible part of the spectrum with wavelengths longer than that of visible red light - we concluded that the outermost ring must be more neutral in color than the innermost ring,” Hammel explained.

The new discoveries by Showalter and Lissauer, made in visible light with Hubble’s Advanced Camera for Surveys, are faint, dusty rings orbiting well beyond Uranus’s previously known system of 11 distinct rings. This brings the total number of known rings up to 13. Uranus also has 27 known moons, one of which, Mab, seems associated with the outermost new ring.

When the Keck team was first informed of the discovery a few months ago, de Pater carefully processed data they had obtained in August with the infrared camera on the 10-meter Keck II telescope. After combining 30 images (equal to a full hour of integration time), she spotted the innermost of the two new faint rings. In subsequent observations in October, the team specifically looked farther from the planet, but failed to see the outermost of the two new rings.

The innermost new ring is about 67,700 kilometers from Uranus, just outside the previously known outermost and brightest ring, called the epsilon ring. This is in accord with the NASA team’s results - that the peak brightness of the innermost new ring is 67,300 kilometers from the center of the planet. The outermost ring, which de Pater and her team did not see, was reported to have a peak brightness at 97,700 kilometers from the planet’s center.

De Pater, Hammel and Gibbard have been observing the planet since 2000 with the second-generation NIRC2 using the adaptive optics system on the Keck II telescope. Last year, they spotted an inner ring, the 11th, that was seen only once before by the Voyager spacecraft.

The team has uncovered various other interesting aspects of the Uranian rings. They saw, for example, that faint dust sheets in between the main rings do not have the same spatial brightness distribution as the dust seen by the Voyager spacecraft almost 20 years earlier in forward scattered visible light. These results have just been published in the Jan. 2006 issue of Icarus.

De Pater’s research is supported by the National Science Foundation and the Technology Center for Adaptive Optics at UC Santa Cruz. Hammel is supported by the National Aeronautics and Space Administration (NASA), while Gibbard is supported by the U.S. Department of Energy’s National Nuclear Security Administration.

Press Release Courtesy of UC Berkeley.

PRECURSOR TO PROTEINS AND DNA FOUND IN STELLAR DISK

MAUNA KEA, Hawaii (December 20th, 2005) Astronomers at W. M. Keck Observatory have found – for the first time – some of the basic compounds necessary to build organic molecules and one of the bases found in DNA within the inner regions of a planet-forming disk. The object, known as “IRS 46,” is located in the Milky Way galaxy, about 375 light years from Earth, in the constellation Ophiuchus. The results will be published in an upcoming issue of the Astrophysical Journal Letters.

“We see prebiotic organic molecules in comets and the gas giant planets in our own solar system and wonder, where did these chemicals come from?” said Dr. Marc Kassis, support astronomer at the W. M. Keck Observatory. “The Spitzer Space Telescope is letting us study these young stellar objects in new and revealing ways, giving us exciting clues about where life may form in the universe.”

The two organic compounds found—acetylene and hydrogen cyanide—are commonly found in our own solar system, such as the atmospheres of the giant gas planets, the icy surfaces of comets, and the atmosphere of Saturn’s largest moon, Titan. Another carbon-containing species detected, carbon dioxide, is widespread in the atmospheres of Venus, the Earth, and Mars.

“If you add hydrogen cyanide, acetylene and water together in a test tube, and give them an appropriate surface on which to be concentrated and react, you’ll get a slew of organic compounds including amino acids and a DNA purine base called adenine,” said Keck Astronomer Dr. Geoffrey Blake, of the California Institute of Technology in Pasadena and co-author of the paper. “Now, we can detect these same molecules in the planet zone of a star hundreds of light-years away.”

The presence of gas-rich disks around young stars is well known, but little is understood about the chemical structure inside. The discovery of acetylene and hydrogen cyanide in one of these disks will help astronomers better understand these disks, where future solar systems may someday form and possibly result in life.

“Spitzer found something very unique—a young protostar with a dusty disk that, when viewed from Earth, appears tilted on the sky, similar to how some galaxies appear,” Kassis explained. “This viewing angle let the team use Keck-NIRSPEC data to study the inner regions of the disk. The results told the team exactly how the disk was moving and suggest there may be a stellar wind coming from the inner region. Keck also helped measure the high temperatures and the particle concentration in the disk.”

The dust and gas surrounding a young star blocks visible light, but lets longer wavelengths, such as infrared light, pass through. Astronomers can find out what this gas and dust is made of by separating the light into its component wavelengths, or colors.

Since 2003, the NASA Spitzer Space Telescope has allowed astronomers to use this technique to study molecular compounds in protoplanetary disks of young stellar objects. The Spitzer “c2d legacy program” has looked at more than 100 sources in five nearby star-forming regions and only one – IRS 46 – showed clear evidence of containing the organic compounds in the warm regions close to the star where terrestrial planets are most likely to form.

“This infant system might look a lot like ours did billions of years ago, before life arose on Earth,” said Fred Lahuis of Leiden Observatory in the Netherlands and the SRON Netherlands Institute for Space Research. Lahuis is the lead author of the paper describing the results.

While the precise events leading up to self-replicating nucleic acids remains unclear, the molecules of acetylene (C2H2) and hydrogen cyanide (HCN) have been shown to produce the base compounds necessary to build RNA and DNA. The team found that the abundance of hydrogen cyanide (HCN) was nearly 10,000 times higher than that found in cold interstellar gas from which stars and planets are born.

Models of early solar-system chemistry have historically centered on data from our own primitive solar system, but now discoveries of protoplanetary disks have opened the field to solar systems other than our own. Theoretical models have suggested that large quantities of complex organic molecules would be present in the inner-most regions of these disks, but until now, no observational tests have been possible.

To help determine where, exactly, the organic-rich gas resides in IRS 46, the team also used submillimeter data from the James Clerk Maxwell Telescope on Mauna Kea. The faint signals observed again suggest that the material originates from the inner disk, perhaps no more 10 astronomical units from the parent star, similar in distance to where Saturn orbits the Sun in our own solar system. However, much additional work remains to be done to know this for certain.

“The gases are very warm, close to or somewhat above the boiling point of water on Earth,” said Dr. Adwin Boogert, also of Caltech. “These high temperatures helped to pinpoint the location of the gases in the disk.”

The Keck-NIRSPEC results point to the presence of a stellar wind emerging from the inner region of the disk orbiting IRS 46. The wind may eventually blow away the dusty debris in the disk, perhaps revealing the presence of rocky, Earth-like planets in several million years.

The Jet Propulsion Laboratory manages the Spitzer Space Telescope mission for NASA’s Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech. JPL is a division of Caltech.

The W. M. Keck Observatory is managed by the California Association for Research in Astronomy, a non-profit 501 (c) (3) corporation. The Keck I and Keck II 10-meter telescopes probe the faintest objects in the optical and infrared Universe. On the Web at keckobservatory.org.

HIGH RES IMAGES OF GALACTIC CENTER

UCLA PRESS RELEASE (December 12th, 2005) UCLA astronomers and colleagues published the first high-resolution images of the center of our Milky Way galaxy, including the area surrounding the supermassive black hole, using a new technology at the W.M. Keck Observatory in Hawaii.

“Everything is much clearer now,” said Andrea Ghez, UCLA professor of physics and astronomy, who headed the research team. “We used a laser to improve the telescope’s vision – a spectacular breakthrough that will help us understand the black hole’s environment and physics. It’s like putting on glasses, and will revolutionize what we can do in astronomy.”

The new technology, called Laser Guide Star Adaptive Optics, will lead to important advances for the study of planets in our solar system and outside of our solar system, as well as galaxies, black holes, and how the universe formed and evolved, Ghez said.

“We have worked for years on techniques for ‘beating the distortions in the atmosphere’ and producing high-resolution images,” she said. “We are pleased to report the first Laser Guide Star Adaptive Optics observations of the center of our galaxy.”

Ghez and her colleagues took “snapshots” of the center of the galaxy, targeting the supermassive black hole 26,000 light years away, at different wavelengths. This approach allowed them to study substantial emission emanating from an enormous hot plasma just outside the black hole’s “event horizon,” about to be pulled through. Plasma is a hot, ionized, gas-like matter – the fourth state of matter, distinct from solids, liquids and gases – believed to make up more than 99 percent of the visible universe, including the stars, galaxies and the vast majority of the solar system.

“We are learning the conditions of the plasma and whether this plays a role in the growth of the supermassive black hole,” Ghez said. “The plasma varies dramatically in intensity from week-to-week, day-to-day, and even within a single hour.”

The research, federally funded by the National Science Foundation, will be published Dec. 20 in the Astrophysical Journal Letters.

The research was conducted using the 10-meter Keck II Telescope, which is the world’s first 10-meter telescope with a laser. Laser Guide Star Adaptive Optics allows astronomers to generate an artificial guide star exactly where they want it, helping to reveal the atmosphere’s distortions.

Since 1995, Ghez has been using the W.M. Keck Observatory to study the galactic center and the movement of 200 nearby stars.

Black holes are collapsed stars so dense that nothing can escape their gravitational pull, not even light. Black holes cannot be seen directly, but their influence on nearby stars is visible, and provides a signature, Ghez said. The supermassive black hole, with a mass more than three million times that of our sun, is in the constellation of Sagittarius. The galactic center is located due south in the summer sky.

The black hole came into existence billions of years ago, perhaps as very massive stars collapsed at the end of their life cycles and coalesced into a single, supermassive object, Ghez said.

Co-authors on the research include UCLA graduate students Seth Hornstein and Jessica Lu; the adaptive optics team at W. M. Keck Observatory: David Le Mignant, Marcos Van Dam and Peter Wizinowich; Antonin Bouchez (formerly with the W. M. Keck Observatory) and Keith Matthews at Caltech; Mark Morris, a UCLA professor of physics and astronomy; and Eric Becklin, a UCLA professor of physics and astronomy.

RELATED LINKS

Ghez provides more information, and images of the galactic center, at:

Galactic Center (html)

NEW RESULTS SHOW EXPANSION RATE OF THE UNIVERSE IS INCREASING

CALTECH PRESS RELEASE (November 22nd, 2005) Based on an ongoing study of exploding stars in the distant universe, astrophysicists have concluded that the effect of the “dark energy” that is speeding up the expansion of the universe is within 10 percent of that of Albert Einstein’s celebrated cosmological constant. Cosmologists regard this result as a major step forward in understanding the nature of this mysterious property of the universe.

Reporting in an upcoming issue of the journal Astronomy and Astrophysics, an international team using a variety of instruments, including the 10-meter Keck telescopes, show the extent to which supernovae that erupt across the universe compare to those closer to home. Measuring the receding motion of supernovae at great distances has been intensely investigated since 1998, when researchers discovered that supernovae of a given recessional velocity seem to be fainter than they would be if the expansion of the universe was slowing down. This result, which has been observed consistently for the last eight years, strongly implies that the expansion rate of the universe is increasing.

The cause of this acceleration may be some form of exotic energy that causes space to push outwards. Einstein originally proposed a mathematical fudge-factor he called the cosmological constant that would preserve the notion of a universe with no beginning and no end. But when Edwin Hubble demonstrated that the universe was expanding, Einstein abandoned the cosmological constant as his “biggest blunder.”

The best way to study the dark energy, whatever it is, continues to be faraway supernovae, says Richard Ellis, the Steele Family Professor of Astronomy at the California Institute of Technology and one of the authors of the paper. “Improved observations of distant supernovae are the most immediate way in which we can learn more about the mysterious dark energy,” Ellis says. “The present study is a very big step forward in quantity and quality and amazingly suggests that Einstein was pretty close to the mark.”

The research project is known as the Supernova Legacy Survey (SNLS), which aims to discover and examine 700 distant supernovae to map out the history of the expansion of the universe. The survey confirms earlier discoveries that the expansion of the universe proceeded more slowly in the past and is speeding up today. However, the crucial step forward is the discovery that Einstein’s 1917 explanation of a constant energy term for empty space fits the new supernova data very well.

The current paper is based on about one-tenth of the imaging data that will be obtained by the end of the survey. Future results are expected to double or even triple the precision of these findings and conclusively solve several remaining mysteries about the nature of dark energy.

“The significance is huge,” said Professor Ray Carlberg, of the department of astronomy and astrophysics at the University of Toronto. “Our particular observation is at odds with a number of theoretical ideas about the nature of dark energy. They generally predict that it should change its form as the universe expands, and as far as we can see, it doesn’t.”

According to Carlberg, the findings suggest that if a human being were to stand on the surface of Earth when the universe is 10-to-20 times its current age and look up at the night sky, most of the galaxies that we take for granted will be so far away that they’ll be virtually invisible, with perhaps only one galaxy in our visible universe.

The researchers located distant supernovae using an innovative, 384-million pixel camera called MegaCam, built by the Commissariat à l’Energie Atomique, a unit of the French atomic energy agency. “Because of its wide field of view—you can fit four moons in an image—it allows us to measure simultaneously several supernovae, which are rare events,” said lead investigator Pierre Astier, a researcher at the Centre National de la Recherche Scientifique (CNRS).

Ellis contributed a critical piece to this work, using spectrographs mounted on the 10-meter Keck telescopes on Mauna Kea in Hawaii. “Representative supernovae from the program have been examined more closely using the giant aperture of the Keck telescope,” he says. “I find these distant supernovae are strikingly similar to those seen locally, validating their use as cosmic yardsticks and hence strongly supporting our scientific conclusions.”

The Supernova Legacy Survey is a collaborative international effort that uses images from the Canada-France-Hawaii Telescope, a 3.6-metre telescope atop Mauna Kea, a dormant Hawaiian volcano. Over nearly five hundred nights of observing time, the researchers identified a few dozen bright pixels of distant supernovae, then examined their spectra using some of the largest telescopes on earth, including the Keck telescopes and the Frederick C. Gillett Gemini North Telescope on Mauna Kea, the Gemini South Telescope on the Cerro Pachón mountain in the Chilean Andes, and the European Southern Observatory Very Large Telescope (VLT) at the Paranal Observatory in Atacama, Chile.

The research was funded by the Canada-France-Hawaii Telescope, the French agency Commissariat à l’Energie Atomique (CEA), Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences de l’Univers du CNRS, the Natural Sciences and Engineering Research Council of Canada, the National Research Council of Canada’s Herzberg Institute of Astrophysics, the Gemini Observatory, the W.M. Keck Observatory, and the Very Large Telescope Project.

Press Release Courtesy of California Institute of Technology

KECK RELEASES DATA OF GAMMA RAY BURST 051111

MAUNA KEA, Hawaii (November 16th, 2005) Spectral data of gamma-ray burst GRB 051111 were collected with the Keck I telescope on November 11, 2005 (UT). The data is available to the public at:

GRB 051111 Data (compressed file)

Astronomer Jason X. Prochaska of UC Santa Cruz determined that the redshift of the gamma-ray burst is z=1.55.

A full analysis is underway.

HUDSON FOUNDATION INVESTS $75,000 IN W. M. KECK OBSERVATORY

KAMUELA, Hawaii (November 7th, 2005) The W. M. Keck Observatory received a grant of $75,000 from the M.R. and Evelyn Hudson Foundation to improve astronomy research and technology. The grant will support three programs at Keck Observatory: $28,000 for a summit employee breakfast program, $25,000 for a supplemental oxygen program for summit employees, and $22,000 to assist the start-up of the Keck advancement office, including funding a new astronomy lecture series.

“We are grateful to the Trustees of the Hudson Foundation for their generous support of our astronomy research,” said Dr. Frederic Chaffee, director of the Observatory. “The funds provided by the Hudson Foundation directly advance our strategic goals to improve operational efficiency and help us achieve that part of our mission to share our discoveries to inspire the imagination of all.”

Hudson Board Member Dr. C. W. “Wally” Hooser, speaking on behalf of the Foundation reported, “One of Hudson Foundation’s areas of interest is space science and we are convinced that philanthropically investing in the Keck Observatory is a sure long term bet. We believe Keck Observatory will provide fundamental discoveries as profound to human civilization as the building of Alexander the Great’s Library in the fourth century B.C. So much of basic research is like the foundation of a house. You don’t know what the house will look like from the foundation, and yet the foundation is absolutely essential for the house to be a success. The Keck Observatory is building a foundation for all of our futures.”

The Hudson breakfast funds will offer nutritious meals for approximately 50 summit workers to optimize their health and the stamina required to perform in the harsh work environment at the telescopes’ 14,000 foot elevation. Oxygen levels at the summit are only 60% of that at sea level. The oxygen program will provide portable oxygen units for summit workers to use to improve overall work performance and safety. Only recently has the technology been available to develop a compact unit suitable for an individual to use on the job. Keck is the first observatory in the world to make supplemental oxygen available to all its summit workers.

Funds for the new Advancement Office will be used to provide funding for priorities that are essential for the Keck Observatory to develop next generation instrumentation and technologies.

The first Keck telescope began observations in May, 1993. Its twin joined in 1996. Together, the two telescopes are the world’s largest optical and infrared eyes into the Universe, providing astronomers with state-of-the-art technology and instruments to conduct scientific research.

The Observatory employs 124 people and has a 2006 budget of $22,400,000.

MOON DISCOVERED ORBITING 10th PLANET (2003 UB313)

MAUNA KEA, Hawaii (October 3rd, 2005) Scientists are over the moon at the W. M. Keck Observatory and the California Institute of Technology over a new discovery of a satellite orbiting the Solar System’s 10th planet (2003 UB313). The newly discove