Astron. Astrophys. 349, L41-L44 (1999)

Letter to the Editor

Discovery of a faint field methane brown dwarf from ES0 NTT and VLT observations

J.G. Cuby ¹, P. Saracco ², A.F.M. Moorwood ³, S. D'Odorico ³, C. Lidman ¹, F. Comerón ³ and J. Spyromilio <sup>1

1</sup> ESO, Paranal Observatory, Alonso de Cordova 3107, Vitacura, Casilla 19001, Santiago 19, Chile
² Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate, Italy
³ ESO, Karl-Schwarzschild-Strasse 2, D-85748 Garching, Germany

Received 2 July 1999 / Accepted 17 August 1999

Abstract

We report the discovery of an isolated brown dwarf with similar properties to the binary object Gliese 229B and to the newly discovered field brown dwarfs from the SDSS and 2MASS surveys. Although exhibiting similar colors, its magnitude of 20.5 is about 6 magnitudes fainter than Gliese 229B. This is the most distant of the several methane brown dwarfs reported to date, at a distance of 90 pc. Its IR spectrum, although at low S/N given the faintness of the object, is remarkably similar to those of the other methane brown dwarfs.

Key words: stars: low-mass, brown dwarfs techniques: spectroscopic Galaxy: stellar content infrared: stars

Send offprint requests to: J.G. Cuby (jcuby@eso.org)

SIMBAD Objects

Contents

• 1. Introduction
• 2. Observations and data reduction
• 3. Discussion
• References

© European Southern Observatory (ESO) 1999

Online publication: September 2, 1999
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