A Search for Substellar Companions to the Two Nearest Brown Dwarf Systems

Abstract

WISE J104915.57-531906.1 A+B and WISE J085510.83-071442.5 were recently discovered as the third and fourth closest known systems to the Sun, respectively (2.0 and 2.3 pc). The former consists of a L8+T0.5 binary and the latter is a probable Y dwarf and is the coldest known brown dwarf (~250 K). We present a search for common proper motion companions to these brown dwarfs using multi-epoch mid-infrared images from the Spitzer Space Telescope. We have also obtained near-infrared adaptive optics images of WISE J104915.57-531906.1 A+B with the Very Large Telescope to search for companions at smaller separations than reached by Spitzer. No new companions are detected in either system. At projected separations of 25-420" (50-840 AU) for WISE J104915.57-531906.1 A+B and 4-420" (9-970 AU) for WISE J085510.83-071442.5, the Spitzer images are sensitive to companions with M_4.5<21.6 and 21.9, respectively, which correspond to masses of >=1 M_Jup for ages of >=1 Gyr and temperatures of >=150 K. The detection limit in the adaptive optics images of WISE J104915.57-531906.1 A+B is dH~10 at 3-15" (6-30 AU), or >=7 M_Jup for >=1 Gyr.

Astronomical Journal, in press

References in corpus (11)

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• Water Clouds in Y Dwarfs and Exoplanets
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• A New Parallax Measurement for the Coldest Known Brown Dwarf
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Cited by in corpus (6)

• The Spectral Energy Distribution of the Coldest Known Brown Dwarf
• Photometric Monitoring of the Coldest Known Brown Dwarf with the Spitzer Space Telescope
• Hubble Space Telescope astrometry of the closest brown dwarf binary system -- I. Overview and improved orbit
• Rotation periods and astrometric motions of the Luhman 16AB brown dwarfs by high-resolution lucky-imaging monitoring
• A 1.48-2.48 $\mu$m R=28000 spectroscopic atlas of the L7.5 and T0.5 components of the nearest pair of brown dwarfs: Luhman 16AB
• A search for millimeter emission from the coldest and closest brown dwarf with ALMA