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2MASS J09393548–2448279: The coldest and least luminous brown dwarf binary known?

Burgasser, Adam J. and Tinney, C. G. and Cushing, Michael C. and Saumon, Didier and Marley, Mark S. and Bennett, Clara S. and Kirkpatrick, J. Davy (2008) 2MASS J09393548–2448279: The coldest and least luminous brown dwarf binary known? Astrophysical Journal Letters, 689 (1). L53-L56. ISSN 2041-8205. doi:10.1086/595747.

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Determinations of the luminosity and atmospheric properties of the T8 brown dwarf 2MASS J09393548 - 2448279 are presented, based on Spitzer IRAC and IRS observations and ground-based astrometry. We find log_(10)(L_(bol)/L⊙) = -5.69 ± 0.03 for this source, comparable to the current low-luminosity record holder 2MASS J04151954 - 0935066. However, modeling of near- and mid-infrared spectral data indicates an effective temperature of 600 ± 35 K, roughly 100 K cooler than 2M0415. These parameters require a highly inflated radius for 2M0939 (R ≈ 0.13 R⊙) which cannot be reconciled with brown dwarf structure models. However, if this source is an unresolved, equal-mass binary, then the reduced luminosity of each component (L_(bol) ≈ 10^-6 L⊙) can be brought into agreement with the inferred atmospheric parameters for an age of 0.4-12 Gyr and component masses of 0.01-0.05 M⊙. This hypothesis can be tested through future high-resolution imaging and/or spectroscopic observations.

Item Type:Article
Related URLs:
URLURL TypeDescription
Burgasser, Adam J.0000-0002-6523-9536
Tinney, C. G.0000-0002-7595-0970
Cushing, Michael C.0000-0001-7780-3352
Marley, Mark S.0000-0002-5251-2943
Kirkpatrick, J. Davy0000-0003-4269-260X
Additional Information:© 2008 The American Astronomical Society. Received 2008 August 25; accepted 2008 October 17; published 2008 November 20. This publication makes use of data from the Two Micron All Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center (IPAC), and funded by NASA and the NSF. The 2MASS data were obtained from the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology (JPL/Caltech), under contract with NASA. This work is also based in part on observations made with the Spitzer Space Telescope, which is operated by JPL/Caltech under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. C. G. T. acknowledges support from ARC grant DP0774000. Support for D. S.’s work, part of the Spitzer Space Telescope Theoretical Research Program, was provided by NASA. We thank our anonymous referee for her/his prompt review of our original manuscript.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Australian Research CouncilDP0774000
Subject Keywords:binaries: close; stars: fundamental parameters; stars: individual (2MASS J04151954-0935066 2MASS J09393548-2448279); stars: low-mass, brown dwarfs
Issue or Number:1
Record Number:CaltechAUTHORS:BURapjl08
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:13440
Deposited By: Tony Diaz
Deposited On:09 Jul 2009 18:04
Last Modified:08 Nov 2021 22:37

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