The pulsations of ZZ Ceti stars - V. The light curves

The characteristic peaked shape of the light curves of the large-amplitude ZZ Ceti stars is reproduced by non-adiabatic calculations where the horizontal motions and the pressure changes are assumed to be sinusoidal but where the temperature changes in the ionization zone are treated non-linearly. The non-sinusoidal shape is associated with the change between convective and radiative energy transport in the deeper layers of the hydrogen ionization zone. Quantitative agreement with the observations is obtained if the modes which cause the large-amplitude brightness changes are assumed to be of spherical degree |= 1|⁠.