PI: Jacqueline Radigan, University of Toronto, firstname.lastname@example.org
Address: Astronomy Department, 50 St. George Street, Rm 101, Toronto, ON m5s3h4, Canada
CoI: Ray Jayawardhana, University of Toronto
CoI: David Lafreniere, Universite de Montreal
Title: Resolved Spectroscopy and Imaging of the First Triple T-dwarf System
Abstract: We propose to obtain follow-up spectroscopy and imaging of a recently discovered \em triple T-dwarf system. This system, with an unresolved spectral type of T3, was resolved into a hierarchical triple using the LGS AO at Keck II during our 2009B program targeting early T- dwarfs whose NIR colors span the L/T transition. This phase of brown dwarf evolution-characterized by the rapid disappearance of dust clouds and a corresponding blue-ward shift in J-K NIR color of ~2 magnitudes over a very narrow range in T_eff-remains poorly understood, and is complicated by the fact that most observations of L/T transition objects are drawn from a heterogeneous sample, consisting of a high frequency of unresolved binaries, and spanning a wide range of ages and metallicities. As the first resolved triple T-dwarf, our new system constitutes the largest homogeneous sample of early T-dwarfs to date and can therefore provide stringent tests of evolutionary and atmospheric models of the L/T transition. In addition, with an estimated period as low as 10-30 years, the tight separation of the Bab components may be suitable for measuring a dynamical mass over the next several years, fixing yet another physical parameter of the system.
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