Direct Detection of the Brown Dwarf GJ 802B with Adaptive Optics Masking Interferometry

Abstract

We have used the Palomar 200" adaptive optics (AO) system to directly detect the astrometric brown dwarf GJ 802B reported by Pravdo et al. This observation is achieved with a novel combination of aperture masking interferometry and AO. The dynamical masses are 0.175+/-0.021 and 0.064+/-0.032 Msolar for the primary and secondary, respectively. The inferred absolute H-band magnitude of GJ 802B is MH=12.8 resulting in a model-dependent Teff of 1850+/-50 K and mass range of 0.057-0.074 Msolar.