RV-RMS versus photometric variability (peak-to-peak of light curve) for the year 1 (a), year 2 (b), year 3 (c) and year 4 (d) RV measurements sampling. Color bars present the peak-to-peak variation of during the whole HARPS observations and the size-scale presents the estimation of the average v sin i derived from the CCF FWHM described in Sect. 3.1. The calculated value of correlation coefficient ρ_sp and its posterior distribution is presented in each panel.