| Issue |
A&A
Volume 430, Number 3, February II 2005
|
|
|---|---|---|
| Page(s) | 1027 - 1033 | |
| Section | Stellar structure and evolution | |
| DOI | https://doi.org/10.1051/0004-6361:20041353 | |
| Published online | 26 January 2005 | |
Astrometric and spectroscopic confirmation of a brown dwarf companion to GSC 08047-00232 *
VLT/NACO deep imaging and spectroscopic observations
1
European Southern Observatory, Casilla 19001, Santiago 19, Chile e-mail: gchauvin@eso.org
2
Laboratoire d'Astrophysique, Observatoire de Grenoble, 414 rue de la piscine, 38400 Saint-Martin d'Hères, France
3
Laboratoire D'Études Spatiales et d'Instrumentation en Astrophysique, Observatoire de Paris, Bât. 16, 5 Place J. Jansen, 92195 Meudon, France
4
Laboratoire d'Astrophysique, Observatoire Midi-Pyrénées, 57 avenue d'Azereix, BP 826, 65008 Tarbes, France
5
Department of Physics & Astronomy and Center for Astrobiology, Physics & Astronomy Building, UCLA, Los Angeles, CA 90095-1562, USA
6
SIRTF Science Center Infrared Processing and Analysis Center, MS 220-6, Pasadena, CA 91125, USA
7
ONERA, BP 52, 29 avenue de la Division Leclerc, 92320 Châtillon Cedex, France
Received:
25
May
2004
Accepted:
16
September
2004
We report VLT/NACO imaging observations of the stars GSC 08047-00232 and HIP 6856, probable members of the large Tucana-Horologium association. During our previous ADONIS/SHARPII deep imaging survey, a substellar candidate companion was discovered around each star. Based on VLT/NACO astrometric measurements, we find that GSC 08047-00232 and the faint candidate companion near to it share the same proper motion with a significance of 3.1 σ. On the contrary, the candidate companion to HIP 6856 is probably a background object with a significance of 4.3 σ. We also detect a new fainter and closer candidate companion to HIP 6856, but which is likely a background object too with a significance of 4 σ. Recent VLT/NACO spectroscopic measurements of GSC 08047-00232 finally confirm the substellar nature of this young brown dwarf with a derived spectral type M 
. GSC 08047-00232 B, with an estimated mass of 
and an effective temperature of 
K, is presently the third substellar companion identified among young, nearby associations.
Key words: instrumentation: adaptive optics / stars: low-mass, brown dwarfs
© ESO, 2005
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