Looper, Dagny L. and Burgasser, Adam J. and Kirkpatrick, J. Davy and Swift, Brandon J. (2007) Discovery of an M9.5 Candidate Brown Dwarf in the TW Hydrae Association: DENIS J124514.1–442907. Astrophysical Journal Letters, 669 (2). L97-L100. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20100310-092446251
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We report the discovery of a fifth candidate substellar system in the ~5-10 Myr TW Hydrae association: DENIS J124514.1-442907. This object has a NIR spectrum remarkably similar to that of 2MASS J1139511-315921, a known TW Hydrae brown dwarf, with low surface gravity features such as a triangular-shaped H band, deep H_2O absorption, weak alkali lines, and weak hydride bands. We find an optical spectral type of M9.5 and estimate a mass of ≾24 M_(Jup), assuming an age of ~5-10 Myr. While the measured proper motion for DENIS J124514.1-442907 is inconclusive as a test for membership, its position in the sky is coincident with the TW Hydrae association. A more accurate proper-motion measurement, higher resolution spectroscopy for radial velocity, and a parallax measurement are needed to derive the true space motion and to confirm its membership.
|Additional Information:||© 2007 The American Astronomical Society. Received 2007 August 30; accepted 2007 September 20; published 2007 October 12. We thank our referee S. Mohanty for suggestions which significantly improved the manuscript. D. L. L. thanks M. Pitts for comments on the manuscript, M. Cushing for useful discussions, J. Gizis for providing an early copy of his manuscript on the parallax for 2MASS 1207A, and R. Scholz and K. Cruz for providing spectra. We also thank our telescope operators B. Golisch, D. Griep, and H. Nun˜ez, and instrument specialist J. Rayner for their assistance. This publication includes data from the DENIS project, which has been partly funded by the SCIENCE and the HCM plans of the European Commission under grants CT920791 and CT940627. This publication makes use of data products from the Two Micron All Sky Survey (2MASS), 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. This research has made use of the NASA/IPAC Infrared Science Archive (IRSA), which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research used the facilities of the Canadian Astronomy Data Centre operated by the National Research Council of Canada with the support of the Canadian Space Agency. Facilities: Keck:I, Magellan:Clay, IRTF|
|Subject Keywords:||open clusters and associations : individual (TW Hydrae) stars : individual (DENIS J124514.-442907, 2MASS J1207334-393254, 2MASS J1139511-315921); stars : low-mass, brown dwarfs|
|Official Citation:||Dagny L. Looper et al 2007 ApJ 669 L97 doi: 10.1086/523812|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||12 Mar 2010 19:27|
|Last Modified:||26 Dec 2012 11:50|
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