EDP Sciences
Free Access
Volume 426, Number 1, October IV 2004
Page(s) L19 - L23
Section Letters
DOI https://doi.org/10.1051/0004-6361:200400076

A&A 426, L19-L23 (2004)
DOI: 10.1051/0004-6361:200400076


The HARPS survey for southern extra-solar planets

II. A 14 Earth-masses exoplanet around $\mu$ Arae
N. C. Santos1, 2, F. Bouchy3, M. Mayor2, F. Pepe2, D. Queloz2, S. Udry2, C. Lovis2, M. Bazot4, W. Benz5, J.-L. Bertaux6, G. Lo Curto7, X. Delfosse8, C. Mordasini5, D. Naef7, 2, J.-P. Sivan3 and S. Vauclair4

1  Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
    e-mail: nuno.santos@oal.ul.pt
2  Observatoire de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland
3  Laboratoire d'Astrophysique de Marseille, Traverse du Siphon, 13013 Marseille, France
4  Laboratoire d'Astrophysique, Observatoire Midi-Pyrénées, 14 avenue Edouard Belin, 31400 Toulouse, France
5  Physikalisches Institut, Universität Bern, Sidlerstrasse 5, 3012 Bern, Switzerland
6  Service d'Aéronomie du CNRS, BP 3, 91371 Verrières-le-Buisson, France
7  European Southern Observatory, Casilla 19001, Santiago 19, Chile
8  Laboratoire d'Astrophysique de l'Observatoire de Grenoble, 414 rue de la piscine, 38400 Saint Martin d'Hères, France

(Received 25 August 2004 / Accepted 10 September 2004)

In this letter we present the discovery of a very light planetary companion to the star $\mu$ Ara (HD 160691). The planet orbits its host once every 9.5 days, and induces a sinusoidal radial velocity signal with a semi-amplitude of 4.1 m s -1, the smallest Doppler amplitude detected so far. These values imply a mass of $m_2\sin{i}=$ 14  $M_{\oplus}$ (Earth-masses). This detection represents the discovery of a planet with a mass slightly smaller than that of Uranus, the smallest "ice giant" in our Solar System. Whether this planet can be considered an ice giant or a super-earth planet is discussed in the context of the core-accretion and migration models.

Key words: stars: individual: HD 160691 -- planetary systems -- techniques: radial velocities

SIMBAD Objects

© ESO 2004