Doppler tomography of the Hα emission line. The Doppler tomograms are shown in the top left and right panels, obtained considering the solution for the γ-velocity of the extra component of the line (probably generated by the WD) and for the M-dwarf component, respectively. In the bottom panel we show a trailed spectrum of the data (left) and the resulting model based on the map with the γ-velocity of the additional component. See text for a more detailed explanation.