Results of our toy model for the RV signatures (upper panel), and bisector velocity shift (BVS) and curvature (BC; lower panels). It shows the kind of RV modulations that can be induced on a photospheric absorption line by an emission component (broader than the absorption line) that shows a rotational modulation. “P” denotes the peak value of an emission component with a Voigt profile with Gaussian width σ and Lorentzian contribution γ. “Cont” marks the classical veiling continuum added to the model. “A” denotes the RV amplitude of the emission line (maximum RV offset for a sinusoidal modulation), and “RS” is the zero-point redshift of the line. The dashed box shows the values of the bisector velocity as measured by K14, which are similar to those derived from the toy model. Although there is a slight BVS slope, the typical errors at this level can make it very hard to distinguish.