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 (Lbol ≈ 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.
Original language | English (US) |
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Pages (from-to) | L53-L56 |
Journal | Astrophysical Journal |
Volume | 689 |
Issue number | 1 PART 2 |
DOIs | |
State | Published - 2008 |
Externally published | Yes |
Keywords
- Binaries: Close-stars: Fundamental parameters
- Brown dwarfs
- Stars: Individual (2MASS J04151954-0935066, 2MASS J09393548-2448279)
- Stars: Low-mass
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science