Journal or Book Title
The Astrophysical Journal
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.
Burgasser, Adam J.; Kirkpatrick, J. Davy; Cutri, Roc M.; McCallon, Howard; Kopan, Gene; Gizis, John E.; Liebert, James; Reid, I. Neill; Brown, Michael E.; Monet, David G.; Dahn, Conard C.; Beichman, Charles A.; and Skrutskie, Michael F., "Discovery of a Brown Dwarf Companion to Gliese 570ABC: A 2MASS T Dwarf Significantly Cooler than Gliese 229B" (2000). The Astrophysical Journal. 101.