The first moment ⟨ v ⟩ of the He i 6678 Å line from the combined Narval and HARPS spectroscopy (top left). The model for the rotational modulation (see Eq. (1)) for P_rot = 0.897673 d and T₀ = 2 456 185.8380 d is given as a solid blue line and the observations as black dots. Bottom left: residuals of ⟨ v ⟩ after the subtraction of the model. Right: computed Lomb-Scargle periodograms of ⟨ v ⟩ (top) and the residuals (bottom), with f_rot and 2f_rot marked as vertical blue lines.