Eyeing Nature’s Coolest, Faintest Objects
This is an infrared image of the brown dwarf binary HD 130948BC, obtained with the Keck II adaptive optics system. The binary is seen to the upper left, in orbit around a young, much more massive, Sun-like star that is about 600 million years old. Credit: Mr. Trent Dupuy and Dr. Michael Liu (Institute for Astronomy, University of Hawaii).
Measuring the masses of brown dwarfs—the lightest objects ever weighed outside the Solar System—has been a painstaking process that would have been impossible without ultra-sharp images taken with the Keck II Telescope and its world-leading adaptive optics system. These images have such high angular resolution that if a human’s eyes could act like the Keck’s adaptive optics system, he or she would be able to read a magazine from a mile away.
The positional accuracy achieved with such sharp images has enabled astronomers Michael Liu and Trent Dupuy of the Institute for Astronomy at the University of Hawai’i and Michael Ireland of the University of Sydney to determine—for the first time ever—the masses of the coldest brown dwarfs. Interestingly, their results are somewhat at odds with current theoretical predictions, challenging astronomers’ understanding of such cold objects.