HIGH-CONTRAST 3.8 {mu}m IMAGING OF THE BROWN DWARF/PLANET-MASS COMPANION TO GJ 758
- NASA-Goddard Space Flight Center, Greenbelt, MD (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)
- Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
We present L'-band (3.8 {mu}m) MMT/Clio high-contrast imaging data for the nearby star GJ 758, which was recently reported by Thalmann et al. to have one -- possibly two -- faint comoving companions (GJ 758B and 'C', respectively). GJ 758B is detected in two distinct data sets. Additionally, we report a possible detection of the object identified by Thalmann et al. as 'GJ 758C' in our more sensitive data set, though it is likely a residual speckle. However, if it is the same object as that reported by Thalmann et al. it cannot be a companion in a bound orbit. GJ 758B has an H - L' color redder than nearly all known L-T8 dwarfs. Based on comparisons with the COND evolutionary models, GJ 758B has T {sub e} {approx} 560 K{sup +150K}{sub -90 K}{sup +150 K) and a mass ranging from {approx}10-20 M{sub J} if it is {approx}1 Gyr old to {approx} 25-40 M{sub J} if it is 8.7 Gyr old. GJ 758B is likely in a highly eccentric orbit, e {approx} 0.73{sup +0.12}{sub -0.21}, with a semimajor axis of {approx}44 AU{sup +32 AU){sub -14 AU}. Though GJ 758B is sometimes discussed within the context of exoplanet direct imaging, its mass is likely greater than the deuterium-burning limit and its formation may resemble that of binary stars rather than that of Jovian-mass planets.
- OSTI ID:
- 21452777
- Journal Information:
- Astrophysical Journal Letters, Vol. 721, Issue 2; Other Information: DOI: 10.1088/2041-8205/721/2/L177; ISSN 2041-8205
- Country of Publication:
- United States
- Language:
- English
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