The characteristics of M dwarfs bear many observational advantages. They allow to probe for new statistical properties of planetary systems. They allow the detection (and possibly the characterisation) of habitable Super Earths, a planetary regime not yet accessible around Sun-like stars.
I will present the results of our search for planets around M dwarfs, with a particular attention for some remarkable detections obtained in 2007. The case of GJ 674 will illustrate both the detection of a low-mass exoplanet (m sin i = 11 Mearth) and the limitation imposed to the radial-velocity method by the magnetic activity that occasionally spot the stellar surface. With GJ 581, we will talk about a system made of three planets, including 2 Super Earths (m sin i ~ 5 & 8 Mearth) located inside or close from the habitable zone. Finally, with GJ 436 we will see that M dwarfs are privileged targets to measure the radius of the smallest exoplanets.
All these detections are not only interesting individually, they also built up a statistical picture of the planetary formation. For the end of my talk, I will therefore focus on the statistical properties we derive from our observations and how they mesh up with the theory of planet formation.
2008 February 14, 13:30
Centro de AstrofÝsica da Universidade do Porto (Auditorium)
Rua das Estrelas, 4150-762 Porto