Dynamical Masses of the Coolest Brown Dwarfs
T dwarfs are excellent laboratories to study the evolution and the atmospheric physics of both brown dwarfs and extrasolar planets. To date, only a single T dwarf binary has a dynamical mass determination, and more are sorely needed. The prospects of measuring more dynamical masses over the next decade are limited to 6 known short-period T dwarf binaries. We propose here to obtain Long-Term HST/ACS monitoring for the 3 of the 6 binaries which cannot be resolved with AO from the ground. Upon completion, our program will substantially increase the number of T dwarf dynamical mass measurements and thereby provide key benchmarks for testing theoretical models of ultracool objects.
Orbital monitoring of 3 methane brown dwarf (T dwarf) binaries. This is a long-term program with 6 epochs of imaging per target over 3 years. One PSF star (eps IndiBab) will be observed in the first year (Cycle 17). Images should be taken at an interval of at least a few months, which drives the requested time constraints. If images are taken too close together in time they become much less useful in determining the orbits of our targets.
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