(Top panel) ESPRESSO CCF FWHM (dots) as a function of time, along with the best sinusoidal model (black line) with a rotation period of 47.19 d (linear trend shown by the straight green line). The 1σ uncertainty of the model is depicted by the gray-shaded area. (Bottom panel) Observed minus computed diagram displaying the FWHM residuals. The derived jitter term (thin vertical line) is quadratically added to the nominal errors (thick vertical line). Stellar variability is reasonably well approximated by a sinusoidal function.