Name/Affiliation: Hugh Harris, Conard Dahn, Trent Dupuy (U.S. Naval Observatory, Flagstaff)
Astrometric Orbits and Masses for Three Low-mass Binaries
Masses for low-mass stars and brown dwarfs are best determined dynamically using binary systems. Accurate astrometry of the photocenter of the unresolved binary, combined with one observation resolving the binary, can be used to determine the orbital elements. We present data for three systems, two heretofore unknown binaries and one previously studied. The orbital periods range from 7 to 13 years, a range where astrometric orbits can be well determined. Gaia data can help with these ground-based solutions, even with its partial orbital coverage, by providing accurate astrometric data for reference stars as well as the binaries.