Top panel: periodogram of our RV time series. Middle panel: periodogram of the Ca II K index interpolated on the same calendar as our RV time series. Lower panel: periodogram of the Ca II K time series with an almost even cadence of one measurement per day. To allow the identification of peaks at short periods, we overplot the periodogram with an amplitude amplified by a factor of five up to a period of about 300 days (green solid line). The dotted vertical lines in the three plots indicate the solar synodic rotation period and its first harmonic, respectively.