Identification of a wide, low-mass multiple system containing the brown dwarf 2MASS J0850359+105716
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Faherty-2011-IDENTIFICATION OF A.pdf
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Author(s)
Faherty, Jacqueline K.
Burgasser, Adam J.
Bochanski, John J.
Looper, Dagny L.
West, Andrew A.
van der Bliek, Nicole S.
Date Issued
January 2011
Journal
Astronomical Journal
Publisher
IOP Publishing
Citation
Faherty, Jacqueline K., Adam J. Burgasser, John J. Bochanski, Dagny L. Looper, Andrew A. West, and Nicole S. van der Bliek. “Identification of a Wide, Low-Mass Multiple System Containing the Brown Dwarf 2MASS J0850359+105716.” The Astronomical Journal 141, no. 3 (January 26, 2011): 71. © 2011 The American Astronomical Society
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Final published version
Abstract
We report our discovery of NLTT 20346 as an M5+M6 companion system to the tight binary (or triple) L dwarf 2MASS J0850359+105716. This nearby (~31 pc), widely separated (~7700 AU) quadruple system was identified through a cross-match of proper motion catalogs. Follow-up imaging and spectroscopy of NLTT 20346 revealed it to be a magnetically active M5+M6 binary with components separated by ~2'' (50-80 AU). Optical spectroscopy of the components shows only moderate Hα emission corresponding to a statistical age of ~5-7 Gyr for both M dwarfs. However, NLTT 20346 is associated with the XMM-Newton source J085018.9+105644, and based on X-ray activity the age of NLTT 20346 is between 250 and 450 Myr. Strong Li absorption in the optical spectrum of 2MASS J0850+1057 indicates an upper age limit of 0.8-1.5 Gyr, favoring the younger age for the primary. Using evolutionary models in combination with an adopted system age of 0.25-1.5 Gyr indicates a total mass for 2MASS J0850+1057 of 0.07 ± 0.02 M [subscript ☉], if it is a binary. NLTT 20346/2MASS J0850+1057 joins a growing list of hierarchical systems containing brown dwarf binaries and is among the lowest binding energy associations found in the field. Formation simulations via gravitational fragmentation of massive extended disks have successfully produced a specific analog to this system.
MIT Department
MIT Kavli Institute for Astrophysics and Space Research
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DOI of Published Version
https://doi.org/10.1088/0004-6256/141/3/71
