BD+20 1790 b : chronicle of an exoplanetary discovery

Abstract

In this contribution we report evidence for a planetary companion around a young and active late-type K star. Our group has been developing a study of stellar activity and kinematics for this star over the past years. Previous results show a high level of stellar activity, with the presence of prominence-like structures, spots on surface and strong flare events. Radial velocity (RV) variations with a semi-amplitude of up to 1 km s−1 were detected. When the nature of these variations were investigated it was found that they are not due to stellar activity. Based upon the analysis of bisector velocity span, as well as Ca II H & K emission, we report that the best explanation for RV variation is the presence of a sub-stellar companion. The Keplerian fit of the RV data yields an orbital solution for a close-in massive planet with an orbital period of 7.783 days. Also, the presence of this close-in massive planet chould be an interpretation for the high level of stellar activity detected.