Near-infrared Multi-band Photometry of the Substellar Companion GJ 758 B
Abstract
GJ 758 B is a cold (~600 K) companion to a Sun-like star at 29 AU projected separation, which was recently detected with high-contrast imaging. Here, we present photometry of the companion in seven photometric bands from Subaru/HiCIAO, Gemini/NIRI, and Keck/NIRC2, providing a rich sampling of the spectral energy distribution in the 1-5 μm wavelength range. A clear detection at 1.58 μm combined with an upper limit at 1.69 μm shows methane absorption in the atmosphere of the companion. The mass of the companion remains uncertain, but an updated age estimate indicates that the most likely mass range is ~30-40 M jup. In addition, we present an updated astrometric analysis that imposes tighter constraints on GJ 758 B's orbit and identifies the proposed second candidate companion, "GJ 758 C," as a background star.
Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, on Gemini data under program GN-2010A-Q-23, and on Keck data under N068N2.- Publication:
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The Astrophysical Journal
- Pub Date:
- February 2011
- DOI:
- arXiv:
- arXiv:1011.5505
- Bibcode:
- 2011ApJ...728...85J
- Keywords:
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- brown dwarfs;
- planetary systems;
- techniques: high angular resolution;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 10 pages, 4 figures, accepted for publication in ApJ Letters. New version: Corrected a few numbers in the astrometry section (which were already correct in the print version, but were based on an outdated simulation in the astro-ph version)