Fire Spectroscopy of Five Late-type T Dwarfs Discovered with the Wide-field Infrared Survey Explorer
Abstract
We present the discovery of five late-type T dwarfs identified with the Wide-field Infrared Survey Explorer (WISE). Low-resolution near-infrared spectroscopy obtained with the Magellan Folded-port InfraRed Echellette reveal strong H_2O and CH_4 absorption in all five sources, and spectral indices and comparison to spectral templates indicate classifications ranging from T5.5 to T8.5:. The spectrum of the latest-type source, WISE J1812+2721, is an excellent match to that of the T8.5 companion brown dwarf Wolf 940B. WISE-based spectrophotometric distance estimates place these T dwarfs at 12-13 pc from the Sun, assuming they are single. Preliminary fits of the spectral data to the atmosphere models of Saumon & Marley indicate effective temperatures ranging from 600 K to 930 K, both cloudy and cloud-free atmospheres, and a broad range of ages and masses. In particular, two sources show evidence of both low surface gravity and cloudy atmospheres, tentatively supporting a trend noted in other young brown dwarfs and exoplanets. In contrast, the high proper motion T dwarf WISE J2018–7423 exhibits a suppressed K-band peak and blue spectrophotometric J – K colors indicative of an old, massive brown dwarf; however, it lacks the broadened Y-band peak seen in metal-poor counterparts. These results illustrate the broad diversity of low-temperature brown dwarfs that will be uncovered with WISE.
Additional Information
© 2011 The American Astronomical Society. Received 2011 March 11; accepted 2011 April 11; published 2011 June 23. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. The authors thank telescope operators Mauricio Martinez, Sergio Vara, and Jorge Araya at Magellan for their assistance with the FIRE and LDSS-3 observations, and T. Jarrett for providing scripts and guidance for the WIRC imaging data reduction. A.J.B. acknowledges financial support from the Chris and Warren Hellman Fellowship Program. This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This publication also makes use of data products from NEOWISE, which is a project of the Jet Propulsion Laboratory/California Institute of Technology, funded by the Planetary Science Division of the National Aeronautics and Space Administration. 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. 2MASS data were obtained from 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. The Digitized Sky Surveys were produced at the Space Telescope Science Institute under U.S. Government grant NAGW-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The Second Palomar Observatory Sky Survey (POSS-II) was made by the California Institute of Technology with funds from the National Science Foundation, the National Geographic Society, the Sloan Foundation, the Samuel Oschin Foundation, and the Eastman Kodak Corporation. The Oschin Schmidt Telescope is operated by the California Institute of Technology and Palomar Observatory. This research has also made use of the SIMBAD database, operated at CDS, Strasbourg, France; the M, L, and T dwarf compendium housed at http://DwarfArchives.org and maintained by Chris Gelino, Davy Kirkpatrick, and Adam Burgasser; and the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at http://www.browndwarfs.org/spexprism. Facilities: AAT (IRIS2), FMO:31in (FANCAM), Magellan: Baade (FIRE),Magellan: Clay (LDSS-3), Hale (WIRC), SOAR (SpartanIRC)Attached Files
Published - Burgasser2011p14658Astrophys_J.pdf
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Additional details
- Eprint ID
- 24378
- Resolver ID
- CaltechAUTHORS:20110712-104928483
- Chris and Warren Hellman Fellowship Program
- NSF
- NAGW-2166
- NASA
- National Geographic Society
- Alfred P. Sloan Foundation
- Samuel Oschin Foundation
- Eastman Kodak Corporation
- NASA/JPL/Caltech
- Created
-
2011-07-12Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Infrared Processing and Analysis Center (IPAC)