Dynamical mass of GJ 802b: A brown dwarf in a triple system

M. J. Ireland, A. Kraus, F. Martinache, J. P. Lloyd, P. G. Tuthill

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72 Citations (Scopus)


We report a dynamical measurement of the mass of the brown dwarf GJ 802B using aperture-masking interferometry and astrometry. In addition, we report the discovery that GJ 802A is itself a close spectroscopic noneclipsing binary with a 19 hr period. We find the mass of GJ 802B to be 0.063 ±0.005 M . GJ 802 has kinematics inconsistent with a young star and more consistent with the thick-disk population, implying a system age of ∼10 Gyr. However, model evolutionary tracks for GJ 802B predict system ages of ∼2 Gyr, suggesting that brown dwarf evolutionary models may be underestimating luminosity for old brown dwarfs.

Original languageEnglish
Pages (from-to)463-471
Number of pages9
JournalAstrophysical Journal
Issue number1
Publication statusPublished - 1 May 2008
Externally publishedYes


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