Substellar Astrophysics from Brown Dwarf Binaries

摘要: We are conducting an imaging survey of the coolest known brown dwarfs using the new Keck laser guide star adaptive optics (LGS AO) system. Our goals are (1) to assess the binary frequency of ultracool (late-L and T-type) brown dwarfs;(2) to find new substellar binaries suitable for dynamical mass determinations;(3) to study the physical processes of substellar photospheres using binaries, which constitute systems of common metallicity and age; and (4) to search for objects of exceptionally low temperature as companions to nearby brown dwarfs. We present newly discovered L and T dwarf binaries related to each of these goals. LGS AO is a key capability for this science as it provides the highest possible angular resolution for near-IR imaging.