Time series data of (from top to bottom) radial velocities (in m s^-1), S index, and Hα index (in 10^-2) are shown in panels a, c, and e, respectively, as observed (black dots) and their linear trend is indicated by the blue lines. The mean errors of each dataset are illustrated by the red line on the lower left side of each panel. Panels b, d, and f show the de-trended data (i.e., linear fit subtracted) folded to the most prominent periodicity at 16.3 days and with zero phase corresponding to the first observation (black dots) and a simple sinusoidal fit (blue curve).