I. Boisse, F. Bouchy, G. Hébrard, X. Bonfils, N. C. Santos, S. Vauclair
Photospheric stellar activity (i.e. dark spots or bright plages) might be an important source of noise and confusion in the radial-velocity (RV) measurements. Radial-velocimetry planet search surveys as well as follow-up of photometric transit surveys require a deep understanding and precise characterization of the effects of stellar activity, in order to disentangle it from planetary signals.
We simulate dark spots on a rotating stellar photosphere. The variations of the RV are characterized and analyzed according to the stellar inclination, the latitude and the number of spots. The Lomb-Scargle periodograms of the RV variations induced by activity present power at the rotational period Prot of the star and its two-first harmonics Prot/2 and Prot/3. Three adjusted sinusoids fixed at the fundamental period and its two-first harmonics allow to remove about 90% of the RV jitter amplitude. We apply and validate our approach on four known active planet-host stars: HD189733, GJ 674, CoRoT-7 and ɩHor.
EPJ Web of Conferences
F. Bouchy, R. Díaz, C. Moutou
Volume 11, Page 02005_1