2MASS J06164006−6407194: the first outer halo L subdwarf
Abstract
We present the serendipitous discovery of an L subdwarf in the Two Micron All Sky Survey (2MASS) J06164006–6407194, in a search of the 2MASS for T dwarfs. Its spectrum exhibits features indicative of both a cool and metal poor atmosphere including a heavily pressure-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and enhanced collision induced absorption of H2. We assign 2MASS J0616–6407 a spectral type of sdL5 based on a comparison of its red optical spectrum to that of near solar-metallicity L dwarfs. Its high proper motion (μ = 1".405 ± 0.008 yr^–1), large radial velocity (V_rad = 454 ± 15 km s_–1), estimated u, v, w velocities (94, –573, 125) km s^–1 and Galactic orbit with an apogalacticon at ~29 kpc are indicative of membership in the outer halo making 2MASS J0616–6407 the first ultracool member of this population.
Additional Information
© 2009 American Astronomical Society. Print publication: Issue 1 (2009 May 1); received 2009 January 5; accepted for publication 2009 February 5; published 2009 April 20. We thank Bill Vacca for fruitful discussions about the reduction of optical spectra and John Bochanski and Andrew West for clarifications on the Galactic orbit geometry. This publication makes use of data from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, and funded by the National Aeronautics and Space Administration and the National Science Foundation, the SIMBAD database, operated at CDS, Strasbourg, France, NASA's Astrophysics Data System Bibliographic Services, the M, L, and T dwarf compendium housed at DwarfArchives.org and maintained by Chris Gelino, Davy Kirkpatrick, and Adam Burgasser, and the NASA/ IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. OSIRIS is a collaborative project between the Ohio State University and Cerro Tololo Inter-American Observatory (CTIO) and was developed through NSF grants AST 90-16112 and AST 92-18449. CTIO is part of the National Optical Astronomy Observatory (NOAO), based in La Serena, Chile. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation. Facilities: Gemini (GMOS), SOAR (OSIRIS), LDSS-3 (Magellan), CTIO (CPAPIR).Attached Files
Published - Cushing2009p2257Astrophys_J.pdf
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Additional details
- Eprint ID
- 14371
- Resolver ID
- CaltechAUTHORS:20090605-134739079
- NASA/JPL/Caltech
- AST 90-16112
- NSF
- AST 92-18449
- NSF
- Created
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2009-08-28Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field