2MASS J09393548-2448279: The Coldest and Least Luminous Brown Dwarf Binary Known?

December 2008 • 2008ApJ...689L..53B

Authors • Burgasser, Adam J. • Tinney, C. G. • Cushing, Michael C. • Saumon, Didier • Marley, Mark S. • Bennett, Clara S. • Kirkpatrick, J. Davy

Abstract • 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 log₁₀(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.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2008ApJ...689L..53B
• PDF https://iopscience.iop.org/article/10.1086/595747/pdf
• DATA https://irsa.ipac.caltech.edu/bibdata/2008/B/2008ApJ...689L..53B.html
• ELECTR https://doi.org/10.1086%2F595747