LESIA - Observatoire de Paris

Planets and Stellar Activity : Hide and Seek in the CoRoT-7 system

jeudi 28 novembre 2013, par Raphaëlle D. Haywood (University of St Andrews)

Mardi 17 décembre 2013 à 11h00 , Lieu : Salle de conférence du bât. 17

Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and masses of planets present in the system, but they all yield different results, owing to the star’s high level of activity. We re-observed CoRoT-7 in January 2012 with both HARPS and CoRoT, so that we now have the benefit of simultaneous radial-velocity and photometric data. This allowed us to use the off-transit variations in the star’s lightcurve to model the radial-velocity variations induced by stellar activity, according to the model described by Aigrain et al. (2012). This model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We use Bayesian methods to assess the evidence for the presence of CoRoT-7d.