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Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf at the L/T Transition

Castro, Philip J. and Gizis, John E. and Harris, Hugh C. and Mace, Gregory N. and Kirkpatrick, J. Davy and McLean, Ian S. and Pattarakijwanich, Petchara and Skrutskie, Michael F. (2013) Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf at the L/T Transition. Astrophysical Journal, 776 (2). Art. No. 126. ISSN 0004-637X. doi:10.1088/0004-637X/776/2/126.

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We discover four high proper motion L dwarfs by comparing the Wide-field Infrared Survey Explorer (WISE) to the Two Micron All Sky Survey. WISE J140533.32+835030.5 is an L dwarf at the L/T transition with a proper motion of 0.85 ± 0."02 yr–1, previously overlooked due to its proximity to a bright star (V ≈ 12 mag). From optical spectroscopy we find a spectral type of L8, and from moderate-resolution J band spectroscopy we find a near-infrared spectral type of L9. We find WISE J140533.32+835030.5 to have a distance of 9.7 ± 1.7 pc, bringing the number of L dwarfs at the L/T transition within 10 pc from six to seven. WISE J040137.21+284951.7, WISE J040418.01+412735.6, and WISE J062442.37+662625.6 are all early L dwarfs within 25 pc, and were classified using optical and low-resolution near-infrared spectra. WISE J040418.01+412735.6 is an L2 pec (red) dwarf, a member of the class of unusually red L dwarfs. We use follow-up optical and low-resolution near-infrared spectroscopy to classify a previously discovered fifth object WISEP J060738.65+242953.4 as an (L8 Opt/L9 NIR), confirming it as an L dwarf at the L/T transition within 10 pc. WISEP J060738.65+242953.4 shows tentative CH_4 in the H band, possibly the result of unresolved binarity with an early T dwarf, a scenario not supported by binary spectral template fitting. If WISEP J060738.65+242953.4 is a single object, it represents the earliest onset of CH_4 in the H band of an L/T transition dwarf in the SpeX Library. As very late L dwarfs within 10 pc, WISE J140533.32+835030.5 and WISEP J060738.65+242953.4 will play a vital role in resolving outstanding issues at the L/T transition.

Item Type:Article
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URLURL TypeDescription Paper
Gizis, John E.0000-0002-8916-1972
Mace, Gregory N.0000-0001-7875-6391
Kirkpatrick, J. Davy0000-0003-4269-260X
Additional Information:© 2013 American Astronomical Society. Received 2013 March 11; accepted 2013 August 19; published 2013 October 7. Observations reported here were obtained at the MMT Observatory, a joint facility of the University of Arizona and the Smithsonian Institution. MMT telescope time was granted by NOAO, through the Telescope System Instrumentation Program (TSIP). TSIP is funded by NSF. We thank the anonymous referee for a thorough report that helped to improve the manuscript. We thank the Annie Jump Cannon Fund at the University of Delaware for support. 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 makes use of data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the U.S. Department of Energy. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, University of Cambridge, University of Florida, the French Participation Group, the German Participation Group, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. 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. This research has benefitted from the SpeX Prism Spectral Libraries, maintained by Adam Burgasser at∼adam/browndwarfs/spexprism. This research has made use of the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This research has benefitted from the M, L, and T dwarf compendium housed at and maintained by Chris Gelino, Davy Kirkpatrick, and Adam Burgasser. This research has made use of the VizieR catalog access tool, CDS, Strasbourg, France. This research has made use of the SIMBAD database, operated at CDS, Strasbourg, France. 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 plates were processed into the present compressed digital form with the permission of these institutions.
Funding AgencyGrant Number
University of Delaware Annie Jump Cannon FundUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
W. M. Keck FoundationUNSPECIFIED
U. S. GovernmentNAGW-2166
Subject Keywords: brown dwarfs; infrared: stars; proper motions; stars: distances; stars: individual (WISE J040137.21+284951.7, WISE J040418.01+412735.6, WISEP J060738.65+242953.4, WISE J062442.37+662625.6, WISE J140533.32+835030.5); stars: late-type
Issue or Number:2
Record Number:CaltechAUTHORS:20131223-101654784
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Official Citation: Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf at the L/T Transition Philip J. Castro et al. 2013 ApJ 776 126
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43140
Deposited By: Ruth Sustaita
Deposited On:23 Dec 2013 18:57
Last Modified:10 Nov 2021 16:33

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