Publication Date

2000

Journal or Book Title

The Astrophysical Journal

Abstract

We report the discovery of a widely separated (258.′′3±0.′′4) T dwarf companion to the Gl 570ABC system. This new component, Gl 570D, was initially identified from the Two Micron All Sky Survey (2MASS). Its near-infrared spectrum shows the 1.6 and 2.2 μm CH4 absorption bands characteristic of T dwarfs, while its common proper motion with the Gl 570ABC system confirms companionship. Gl 570D (MJ = 16.47±0.07) is nearly a full magnitude dimmer than the only other known T dwarf companion, Gl 229B, and estimates of L = (2.8±0.3)x10−6 L⊙ and Teff = 750±50 K make it significantly cooler and less luminous than any other known brown dwarf companion. Using evolutionary models by Burrows et al. and an adopted age of 2-10 Gyr, we derive a mass estimate of 50±20 MJup for this object.

Comments

This is a pre-published version which is collected from arXiv. The published version is at http://iopscience.iop.org/1538-4357/531/1/L57.

Volume

531

Pages

L57-L60

Issue

1

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