Searching for Binary Y Dwarfs with the Gemini Multi-conjugate Adaptive Optics System (GeMS)

March 2016 • 2016ApJ...819...17O

Authors • Opitz, Daniela • Tinney, C. G. • Faherty, Jacqueline K. • Sweet, Sarah • Gelino, Christopher R. • Kirkpatrick, J. Davy

Abstract • The NASA Wide-field Infrared Survey Explorer (WISE) has discovered almost all the known members of the new class of Y-type brown dwarfs. Most of these Y dwarfs have been identified as isolated objects in the field. It is known that binaries with L- and T-type brown dwarf primaries are less prevalent than either M-dwarf or solar-type primaries, they tend to have smaller separations and are more frequently detected in near-equal mass configurations. The binary statistics for Y-type brown dwarfs, however, are sparse, and so it is unclear if the same trends that hold for L- and T-type brown dwarfs also hold for Y-type ones. In addition, the detection of binary companions to very cool Y dwarfs may well be the best means available for discovering even colder objects. We present results for binary properties of a sample of five WISE Y dwarfs with the Gemini Multi-Conjugate Adaptive Optics System. We find no evidence for binary companions in these data, which suggests these systems are not equal-luminosity (or equal-mass) binaries with separations larger than ∼0.5-1.9 AU. For equal-mass binaries at an age of 5 Gyr, we find that the binary binding energies ruled out by our observations (I.e., 10⁴² erg) are consistent with those observed in previous studies of hotter ultra-cool dwarfs.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2016ApJ...819...17O
• PDF https://iopscience.iop.org/article/10.3847/0004-637X/819/1/17/pdf
• PDF https://stacks.iop.org/0004-637X/819/17/pdf
• PREPRINT http://arxiv.org/abs/1601.05508
• DATA https://archive.gemini.edu/searchform/publication=2016ApJ...819...17O
• ELECTR https://doi.org/10.3847%2F0004-637X%2F819%2F1%2F17