Convective overshooting in white dwarf and ZZ Ceti stars

The light curves of ZZ Ceti stars exhibit variations of luminosity with typical intervals between successive pulses in the range from the hundreds to the second thousands, and, in general, the “periods” are not constant. The oscillations and pulsations (non radial g modes) in ZZ Ceti stars are usually attributed to temperature intrinsic variations (Väth et al. 2001). In standard ZZ Ceti asteroseismology the possibility of heat propagation by waves is obviated in the energy transport equation. This simplification will be spurious in the degenerate material because, the relaxation time is not negligible. The temperature gradient in stars is given, in a good approximation, by the energy transport equation