English

Dynamical Mass of GJ 802B: a brown dwarf in a triple system

Astrophysics 2009-11-13 v1

Abstract

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 non-eclipsing binary with a 19 hour period. We find the mass of GJ 802B to be 0.063±0.0050.063\pm0.005M\sun_\sun. GJ 802 has kinematics inconsistent with a young star and more consistent with the thick disk population, implying a system age of \sim10 GYr. However, model evolutionary tracks for GJ 802B predict system ages of \sim2 GYr, suggesting that brown dwarf evolutionary models may be underestimating luminosity for old brown dwarfs.

Cite

@article{arxiv.0801.1525,
  title  = {Dynamical Mass of GJ 802B: a brown dwarf in a triple system},
  author = {M. J. Ireland and A. Kraus and F. Martinache and J. P. Lloyd and P. G. Tuthill},
  journal= {arXiv preprint arXiv:0801.1525},
  year   = {2009}
}

Comments

10 pages, 6 figures, accepted for ApJ

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