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Paper: The Effects of Crystallization on the Pulsational Properties of Massive ZZ Ceti Stars
Volume: 334, 14th European Workshop on White Dwarfs
Page: 537
Authors: Corsico, A.H.; Althaus, L.G.; Montgomery, M.H.; Garcia-Berro, E.
Abstract: We present pulsational calculations for improved carbon-oxygen DA white dwarf (WD) models suitable for massive ZZ Ceti stars. The background models employed in this study are the result of the complete evolution of massive WD progenitors from the zero-age main sequence through the Asymptotic Giant Branch (AGB) and mass loss phases to the WD regime (Althaus et al. 2003). Abundance changes are accounted for by means of a full coupling between nuclear evolution and time-dependent mixing due to convection and diffusive overshoot. In addition, time-dependent element diffusion for multicomponent gases has been considered during the WD evolution. Crystallization and chemical rehomogenization due to phase separation upon crystallization in the core of our models have been fully considered. We discuss the implications of our study for BPM 37093, the most massive ZZ Ceti star presently known. In particular, we attempt to place constraints on the physical processes occurring prior to the formation of this WD. We find that if BPM 37093 has a stellar mass of ≈ 1.00MSolar, its observed spectrum could bear the signature of overshoot episodes during the helium core burning.
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