Astron. Astrophys. 338, L67-L70 (1998)

Letter to the Editor

The closest extrasolar planet

A giant planet around the M4 dwarf Gl 876 ^{*, **}

X. Delfosse ^{1, 2}, T. Forveille ², M. Mayor ¹, C. Perrier ², D. Naef ¹ and D. Queloz <sup>3, 1

1</sup> Observatoire de Genève, 51 Ch des Maillettes, CH-1290 Sauverny, Switzerland
² Observatoire de Grenoble, 414 rue de la Piscine, Domaine Universitaire de St Martin d'Hères, F-38041 Grenoble, France
³ Jet Propulsion Laboratory, Mail Stop 306-473, 4800 Oak Grove Drive, Pasadena, CA 91109, USA

Received 4 August 1998 / Accepted 17 August 1998

Abstract

Precise radial velocity observations of the nearby M4 dwarf Gl 876 with the Observatoire de Haute Provence 1.93 m telescope and the new 1.20 m swiss telescope at la Silla indicate the presence of a jovian mass companion to this star. The orbital fit to the data gives a period of 60.8 days, a velocity amplitude of 246m.s^-1 and an eccentricity of 0.34. Assuming that Gl 876 has a mass of 0.3, the mass function implies a mass for the companion of 2/ Jupiter masses.

Key words: giant planet formation extrasolar planets giant planets M dwarf stars

* Partly based on observations made at the Observatoire de Haute Provence (CNRS)
** Partly based on observations obtained with the swiss 1.2m telescope at the European Southern Observatory

Send offprint requests to: Xavier Delfosse
(e-mail: Xavier.Delfosse@obs.unige.ch)

© European Southern Observatory (ESO) 1998

Online publication: September 14, 1998

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