Teixeira, R. and Ducourant, C. and Chauvin, G. and Krone-Martins, A. and Song, I. and Zuckerman, B. (2008) SSSPM J1102-3431 brown dwarf characterization from accurate proper motion and trigonometric parallax. Astronomy and Astrophysics, 489 (2). pp. 825-827. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:TEIaanda08
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Context. In 2005, Scholz and collaborators discovered, in a proper motion survey, a young brown dwarf SSSPM J1102-3431 (SSSPM J1102) of spectral type M8.5, probable member of the TW Hydrae Association and possible companion of the T Tauri star TWHya. The physical characterization of SSSPM J1102 was based on the hypothesis that it forms a binary system with TWHya. The recent discovery of a probable giant planet with a very short-period inside the TW Hya protoplanetary disk, as well as a disk around SSSPM J1102, make it especially interesting and important to measure well the physical parameters of SSSPM J1102. Aims. Trigonometric parallax and proper motion measurements of SSSPM J1102 are necessary to test for TWA membership and, thus, to determine the mass and age of this young brown dwarf and the possibility that it forms a wide binary system with TW Hya. Methods. Two years of regular observations at the ESO NTT/SUSI2 telescope have enabled us to determine the trigonometric parallax and proper motion of SSSPM J1102. Results. With our accurate distance determination of 55.2+^1.6−1.4 pc and proper motions of (−67.2, −14.0) ± 0.6 mas/yr, we could confirm SSSPM J1102 as a very probable member of TWA. Assuming the TWHydrae association age of 5−10 Myr, the evolutionary models compared to the photometry of this young brown dwarf indicate a mass of M = 25 ± 5 MJup and an effective temperature Teff = 2550 ± 100 K. Conclusions. Our parallax and proper motion determination allow us to precisely describe the physical properties of this low mass object and to confirm its TWA membership. Our results indicate that SSSPMJ1102 may be a very wide separation companion of the star TW Hya.
|Additional Information:||© ESO 2008. Received 5 May 2008 / Accepted 13 June 2008. We would like to thank the staff of ESO-VLT and CFHT and Gilles Chabrier, Isabelle Baraffe, and France Allard for providing the latest update of their evolutionary models. We also acknowledge partial financial support from the Programmes Nationaux de Planétologie et de Physique Stellaire (PNP & PNPS) (in France), the Brazilian Organism FAPESP and CAPES, and French Organism COFECUB.|
|Subject Keywords:||stars: low-mass, brown dwarfs; astrometry; stars: distances; stars: fundamental parameters; Galaxy: open clusters and associations: individual: TW Hya|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||23 Apr 2009 21:58|
|Last Modified:||26 Dec 2012 10:49|
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