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

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

doi:10.1086/595747

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

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

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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.

Original language	English (US)
Pages (from-to)	L53-L56
Journal	Astrophysical Journal
Volume	689
Issue number	1 PART 2
DOIs	https://doi.org/10.1086/595747
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

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title = "2MASS J09393548-2448279: The coldest and least luminous brown dwarf binary known?",

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.",

keywords = "Binaries: Close-stars: Fundamental parameters, Brown dwarfs, Stars: Individual (2MASS J04151954-0935066, 2MASS J09393548-2448279), Stars: Low-mass",

author = "Burgasser, {Adam J.} and Tinney, {C. G.} and Cushing, {Michael C.} and Didier Saumon and Marley, {Mark S.} and Bennett, {Clara S.} and Kirkpatrick, {J. Davy}",

year = "2008",

doi = "10.1086/595747",

language = "English (US)",

volume = "689",

pages = "L53--L56",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "IOP Publishing Ltd.",

number = "1 PART 2",

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TY - JOUR

T1 - 2MASS J09393548-2448279

T2 - The coldest and least luminous brown dwarf binary known?

AU - Burgasser, Adam J.

AU - Tinney, C. G.

AU - Cushing, Michael C.

AU - Saumon, Didier

AU - Marley, Mark S.

AU - Bennett, Clara S.

AU - Kirkpatrick, J. Davy

PY - 2008

Y1 - 2008

N2 - 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.

AB - 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.

KW - Binaries: Close-stars: Fundamental parameters

KW - Brown dwarfs

KW - Stars: Individual (2MASS J04151954-0935066, 2MASS J09393548-2448279)

KW - Stars: Low-mass

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

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