Talk abstract details

Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
R.D. Haywood, A.C. Cameron, D. Queloz, S.C.C. Barros, M. Deleuil, R. Fares, M. Gillon, A. Hatzes, A.F. Lanza, C. Lovis, C. Moutou, F. Pepe, D. Pollacco, A. Santerne, D. Ségransan and Y. Unruh


In July 2009, Léger et al. announced the discovery of the transiting Super-Earth CoRoT-7b.
Since then, several investigations on the number and precise masses of planets present in the system have been made, but they all yield different results. This is due to the star's high level of activity.
Radial velocity variations induced by stellar activity therefore need to be modelled and removed to allow a reliable detection of all planets in the system. We re-observed CoRoT-7 in January 2012 with both HARPS and the CoRoT satellite, so that we now have the benefit of simultaneous radial velocity and photometric data.
We fitted the off-transit variations in the CoRoT lightcurve using a harmonic decomposition similar to that implemented in Queloz et al. (2009).
This fit was then used to model the stellar radial velocity contribution, according to the methods described by Aigrain et al. (2011) and Lanza et al. (2010). This model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of CoRoT-7b and CoRoT-7c's orbits and masses. We also assess any evidence for the presence of one or two additional planetary companions.

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