J/ApJ/794/143 New SpeX Observations of M7-L6 Dwarfs (Bardalez+, 2014)
SpeX spectroscopy of unresolved very low mass binaries.
II. Identification of 14 candidate binaries with late-M/early-L and T dwarf
components.
Bardalez Gagliuffi D.C., Burgasser A.J., Gelino C.R., Looper D.L.,
Nicholls C.P., Schmidt S.J., Cruz K., West A.A., Gizis J.E., Metchev S.
<Astrophys. J., 794, 143 (2014)>
=2014ApJ...794..143B 2014ApJ...794..143B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, dwarfs ; Stars, double and multiple ; Spectral types ;
Photometry, infrared
Keywords: binaries: close - binaries: general - brown dwarfs - stars: low-mass
Abstract:
Multiplicity is a key statistic for understanding the formation of
very low mass (VLM) stars and brown dwarfs. Currently, the separation
distribution of VLM binaries remains poorly constrained at small
separations (≤1 AU), leading to uncertainty in the overall binary
fraction. We approach this problem by searching for late-M/early-L
plus T dwarf spectral binaries whose combined light spectra exhibit
distinct peculiarities, allowing for separation-independent
identification. We define a set of spectral indices designed to
identify these systems, and we use a spectral template fitting method
to confirm and characterize spectral binary candidates from a library
of 815 spectra from the SpeX Prism Spectral Libraries. We present 11
new binary candidates, confirm 3 previously reported candidates, and
rule out 2 previously identified candidates, all with primary and
secondary spectral types in the range M7-L7 and T1-T8, respectively.
We find that subdwarfs and blue L dwarfs are the primary contaminants
in our sample and propose a method for segregating these sources. If
confirmed by follow-up observations, these systems may add to the
growing list of tight separation binaries, whose orbital properties
may yield further insight into brown dwarf formation scenarios.
Description:
The SpeX Prism Library is composed of low-resolution
(λ/Δλ=75-120) spectra acquired with the SpeX
0.8-2.5 um spectrograph, mounted on the 3.0 m NASA Infrared
Telescope Facility (IRTF), located in Mauna Kea, HI (Rayner et al.
2003PASP..115..362R 2003PASP..115..362R). All spectra were obtained using the
prism-dispersed SpeX mode, which continuously samples wavelengths
between 0.75 and 2.5 um at a dispersion of 20-30 Å/pixel.
The library includes close to 2000 sources, both previously published
data (e.g., Burgasser et al. 2010, J/ApJ/710/1142; Chiu et al. 2006,
J/AJ/131/2722; Cruz et al. 2003, J/AJ/126/2421) and 530 new spectra
acquired between 2000 November and 2013 December.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 119 530 New SpeX Observations of M7-L6 Dwarfs
refs.dat 125 90 References
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See also:
J/AJ/126/2421 : 2MASS-Selected sample of ultracool dwarfs (Cruz+, 2003)
J/AJ/131/2722 : New L and T dwarfs from the SDSS (Chiu+, 2006)
J/ApJ/710/1142 : SpeX spectroscopy of low mass binaries. I. (Burgasser+, 2010)
J/AJ/147/34 : SpeX library of L-type dwarfs (Schneider+, 2014)
J/ApJ/802/L10 : M dwarf SpeX NIR spectroscopy (Terrien+, 2015)
J/ApJS/220/16 : SpeX NIR survey of 886 nearby M dwarfs (Terrien+, 2015)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 27 A27 --- Name Source name
29- 47 A19 --- ID Source designation
49- 58 A10 --- OSpType Spectral type from optical spectrum
60- 72 A13 --- NSpType Spectral type from NIR spectrum
74- 79 A6 --- SSpType Spectral type from SpeX observation (1)
81- 86 F6.3 mag Jmag ? 2MASS J band magnitude
88- 92 F5.2 mag J-Ks ? 2MASS (J-KS) color
94-104 A11 "date" Date Date of the observation
106-108 I3 --- Res Resolution
110-119 A10 --- Ref References in refs.dat file (2)
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Note (1): Near-infrared classification from SpeX data based on index method
described in Burgasser (2007ApJ...659..655B 2007ApJ...659..655B).
Note (2): First citation is the discovery reference; next citation(s) are
classification references (optical and near-infrared).
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Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref [1/90] Reference number
4- 22 A19 --- Bibcode Reference bibcode
25- 49 A25 --- Aut Author's name
52-125 A74 --- Com Comment on reference
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History:
* 15-May-2017: From electronic version of the journal
* 23-Oct-2017: 2MASS magnitude of 2MASS J06085283-2753583 corrected with
2MASS data
References:
Burgasser et al., Paper I, 2010ApJ...710.1142B 2010ApJ...710.1142B
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 15-May-2017