Volume 507, Number 1, November III 2009
|Page(s)||487 - 494|
|Section||Planets and planetary systems|
|Published online||24 September 2009|
The HARPS search for southern extra-solar planets*
XVIII. An Earth-mass planet in the GJ 581 planetary system
Observatoire de Genève, Université de Genève, 51 ch. des Maillettes, 1290 Sauverny, Switzerland e-mail: email@example.com
2 Laboratoire d'Astrophysique, Observatoire de Grenoble, Université J. Fourier, CNRS (UMR5571), BP 53, 38041 Grenoble, Cedex 9, France
3 Centro de Astronomia e Astrofísica da Universidade de Lisboa, Observatório Astronómico de Lisboa, Tapada da Ajuda, 1349-018 Lisboa, Portugal
4 Service d'Aéronomie du CNRS, BP 3, 91371 Verrières-le-Buisson, France
5 Institut d'Astrophysique de Paris, CNRS, Université Pierre et Marie Curie, 98bis Bd Arago, 75014 Paris, France
6 Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, P4150-762 Porto, Portugal
Accepted: 14 June 2009
The GJ 581 planetary system is already known to harbour three planets, including two super-Earth planets that straddle its habitable zone. We report the detection of an additional planet – GJ 581e – with a minimum mass of 1.9 . With a period of 3.15 days, it is the innermost planet of the system and has a ~5% transit probability. We also correct our previous confusion about the orbital period of GJ 581d (the outermost planet) with a one-year alias, benefitting from an extended time span and many more measurements. The revised period is 66.8 days, and positions the semi-major axis inside the habitable zone of the low mass star. The dynamical stability of the 4-planet system imposes an upper bound on the orbital plane inclination. The planets cannot be more massive than approximately 1.6 times their minimum mass.
Key words: planetary systems / stars: late-type / techniques: radial velocities / stars: individual: GJ 581
Based on observations made with the HARPS instrument on the ESO 3.6 m telescope under the GTO and LP programs 072.C-0488 and 183.C-0437 at Cerro La Silla (Chile). Our radial-velocity, photometric and Ca II H+K index time series (Table 1) are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/507/487
© ESO, 2009
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.