Subtle Signatures of Multiplicity in Late-type Dwarf Spectra: The Unresolved M8.5 + T5 Binary 2MASS J03202839–0446358

By A. Burgasser, Michael C. Liu, Michael J. Ireland, Kelle Cruz, T. Dupuy. 2008

143 citations recorded by the source corpus.

Evidence is presented that 2MASS J03202839–0446358, a late-type dwarf with discrepant optical (M8:) and near-infrared (L1) spectral types, is an as-yet unresolved stellar/brown dwarf binary with late-type M dwarf and T dwarf components. This conclusion is based on low-resolution, near-infrared spectroscopy that reveals a subtle but distinctive absorption feature at 1.6 μ m . The feature, which is also present in the combined light spectrum of the M8.5 + T6 binary SCR 1845–6357, arises from the combination of FeH absorption from an M8.5 primary and pseudocontinuum flux from a T5 ± 1 secondary, as ascertained from binary spectral templates constructed from empirical data. The binary templates provide a far superior match to the overall near-infrared spectral energy distribution of 2MASS J0320–0446 than any single comparison spectra. Laser guide star adaptive optics (LGS AO) imaging observations, including the first application of LGS AO aperture mask interferometry, fail to resolve a faint companion, restricting the projected separation of the system to less than 8.3 AU at the time of observation. 2MASS J0320–0446 is the second very low mass binary to be identified from unresolved, low-resolution, near-infrared spectroscopy, a technique that complements traditional high-resolution imaging and spectroscopic methods.

Subfields: Astronomy and Astrophysics, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/c764c320642513f497ffc72337ecb1fdc5458aa6

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In Astronomy and Astrophysics

1. Michael C. Liu
2. T. Dupuy
3. A. Burgasser
4. Kelle Cruz
5. J. D. Kirkpatrick
6. K. Allers
7. M. Marley
8. K. Luhman

In Atomic and Molecular Physics, and Optics

1. A. Burgasser
2. J. D. Kirkpatrick
3. Michael C. Liu
4. T. Dupuy
5. Kelle Cruz
6. S. Leggett
7. I. Neill Reid
8. D. Apai

Citations in the corpus

• WEATHER ON OTHER WORLDS. II. SURVEY RESULTS: SPOTS ARE UBIQUITOUS ON L AND T DWARFS (2014, methodology): “′′10, we treat them as single objects in our analysis, although radial velocity monitoring would be needed to establish this with confidence (e.g., Burgasser et al. 2008a).”
• MID-INFRARED PHOTOMETRY OF COLD BROWN DWARFS: DIVERSITY IN AGE, MASS, AND METALLICITY (2010, methodology): “Previously published IRAC photometry for a reference sample of late-type M, L and T dwarfs was taken from Burgasser et al. (2008b); Burningham et al. (2008); Leggett et al. (2007b); Luhman et al. (2007); Patten et al. (2006); Warren et al. (2007).”
• THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION, (2012, result): “…Bowler et al. (2010a); (8) Burgasser et al. (2003a); (9) Burgasser et al. (2006b); (10) Burgasser et al. (2007); (11) Burgasser et al. (2008a); (12) Burgasser et al. (2008b); (13) Burgasser et al. (2009); (14) Burningham et al. (2008); (15) Burningham et al. (2009); (16) Burningham et al. (2010);…”
• THE BROWN DWARF KINEMATICS PROJECT (BDKP). III. PARALLAXES FOR 70 ULTRACOOL DWARFS (2012, background): “…astrometric programs, the spectral-type/absolute magnitude relations and color-magnitude diagrams for brown dwarfs were first investigated (Thorstensen & Kirkpatrick 2003, Costa et al. 2006, Burgasser et al. 2008c, Lucas et al. 2010, Artigau et al. 2010, Schilbach et al. 2009, Marocco et al. 2010).”
• YOUNG L DWARFS IDENTIFIED IN THE FIELD: A PRELIMINARY LOW-GRAVITY, OPTICAL SPECTRAL SEQUENCE FROM L0 TO L5 (2008, background): “This effect has been observed in the unresolved near-infrared spectra of binary MLT dwarfs (Cruz et al. 2004; Burgasser et al. 2008a).”
• SpeX SPECTROSCOPY OF UNRESOLVED VERY LOW MASS BINARIES. I. IDENTIFICATION OF 17 CANDIDATE BINARIES STRADDLING THE L DWARF/T DWARF TRANSITION (2009, methodology): “…Kirkpatrick et al. (2008); (6) K. Cruz, in preparation; (7) Kirkpatrick et al. (2000); (8) Geballe et al. (2002); (9) Burgasser et al. (2004); (10) Burgasser et al. (2008a); (11) Reid et al. (2000); (12) Burgasser (2007c); (13) Mugrauer et al. (2006); (14) Luhman et al. (2007); (15) Burgasser et…”
• THE HAWAII INFRARED PARALLAX PROGRAM. II. YOUNG ULTRACOOL FIELD DWARFS (2016, background): “However, visual inspection of the near-IR SpeX prism spectra for our two high-velocity objects (Allers & Liu 2013a; Burgasser et al. 2008) do not reveal any obvious discrepancies compared to other int-g objects of similar spectral – 27 – type but lower tangential velocity.”
• FUNDAMENTAL PARAMETERS AND SPECTRAL ENERGY DISTRIBUTIONS OF YOUNG AND FIELD AGE OBJECTS WITH MASSES SPANNING THE STELLAR TO PLANETARY REGIME (2015, unknown): “…& Kirkpatrick (2003), (25) Leggett et al. (2012), (26) Gatewood & Coban (2009), (27) Artigau et al. (2010), (28) Schilbach et al. (2009), (29) Burgasser et al. (2008c), (30) Tinney et al. (2003), (31) Lurie et al. (2014), (32)Boffin et al. (2013), (33) Teixeira et al. (2008), (34) Weinberger…”
• THE NIRSPEC ULTRACOOL DWARF RADIAL VELOCITY SURVEY (2010, methodology): “We discovered the SB1 spectroscopic binary system 2M0320−04 early in our survey (Blake et al. 2008b) and its binarity was suggested independently using spectral fitting methods by Burgasser et al. (2008).”