2010A&A...513L...8F

The young active star BD+20 1790 has been inferred to host a substellar companion from radial-velocity measurements that detected the reflex motion induced on the parent star. We attempt to completely characterize the radial-velocity signal in order to assess its nature. We used the CORALIE spectrograph to obtain precise (∼10m/s) radial-velocity measurements of this active star, while characterizing the bisector span variations. We took particular care to correctly sample both the proposed planetary orbital period, of 7.8-days, and the stellar rotation period, of 2.4-days. We measure a smaller radial-velocity signal (with peak-to-peak variations <500m/s) than reported previously, and of different amplitude for two different campaigns. A periodicity similar to the rotational period is found in the data, as well as a clear correlation between radial velocities and bisector span. These results imply that the radial-velocity variations of the star are photospheric in origin and not caused by a barycentric movement movement of the star, and contradict the previous detection of a hot-Jupiter.