The HARPS search for southern extra-solar planets. X. A m sin i = 11 M_⊕ planet around the nearby spotted M dwarf
Context: How planet properties depend on stellar mass is a key diagnostic of planetary formation mechanisms.
Aims: This motivates planet searches around stars that are significantly more massive or less massive than the Sun, and in particular our radial velocity search for planets around very low-mass stars.
Methods: As part of that program, we obtained measurements of
Results: These data are described well by a 2-planet Keplerian model where each planet has a ~11 M_⊕ minimum mass. A careful analysis of the (low-level) magnetic activity of
Conclusions: Its detection adds to the growing number of Neptune-mass planets around M-dwarfs and reinforces the emerging conclusion that this mass domain is much more populated than the Jovian mass range. We discuss the metallicity distributions of M dwarf with and without planets and find a low 11% probability that they are drawn from the same parent distribution. Moreover, we find tentative evidence that the host star metallicity correlates with the total mass of their planetary system. Based on observations made with the HARPS instrument on the ESO 3.6 m telescope under the GTO program ID 072.C-0488 at Cerro La Silla (Chile). Radial-velocity, photometric and Ca II H+K index time series are only available in electronic format the CDS via anonymous ftp to cdsarc.u-strasbg.fr (18.104.22.168) or via http://cdsweb.u-strabg.fr/cgi-bin/qcat?J/A+A/474/293
Astronomy and Astrophysics
- Pub Date:
- October 2007
- stars: individual: <ASTROBJ>GJ 674</ASTROBJ>;
- stars: planetary systems;
- stars: late-type;
- techniques: radial velocities;
- submitted to A&