SpeX Spectroscopy of Unresolved Very Low Mass Binaries. II. Identification of 14 Candidate Binaries with Late-M/Early-L and T Dwarf Components
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.
Additional Information
© 2014 The American Astronomical Society. Received 2014 May 19; accepted 2014 August 12; published 2014 October 2. The authors thank telescope operators for their assistance during the observations. D.B.G. would like to thank the Friends of the International Center at UCSD for their generous scholarship, as well as Davy Kirkpatrick and fellow graduate students Alex Mendez and David Vidmar for their helpful discussion and coding tips. This publication makes use of data from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at http://www.browndwarfs.org/spexprism, the Dwarf Archives Compendium, maintained by Chris Gelino at http://DwarfArchives.org, and the VLM Binaries Archive, maintained by Nick Siegler at http://vlmbinaries.org. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. Facility: IRTF (SpeX)Attached Files
Published - 0004-637X_794_2_143.pdf
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Additional details
- Eprint ID
- 51785
- Resolver ID
- CaltechAUTHORS:20141114-131956386
- Created
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2014-11-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)