Stellar case: light curve for the linear polarization degree (left) and direction (middle), and for the Stokes parameters (right) when the magnetic dipole axis is not aligned with the star rotation axis, which is assumed to lie in the plane of the sky. The polarization direction is given by its rotation with respect to the star rotation axis. p_max is the polarization degree that would be observed at a star limb point in zero magnetic field. This figure replaces Fig. 3 of López Ariste et al. (2011).