EDP Sciences
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Volume 380, Number 1, December II 2001
Page(s) L17 - L20
Section Letters
DOI http://dx.doi.org/10.1051/0004-6361:20011507

A&A 380, L17-L20 (2001)
DOI: 10.1051/0004-6361:20011507

New DA white dwarf evolutionary models and their pulsational properties

A. H. Córsico, L. G. Althaus, O. G. Benvenuto and A. M. Serenelli

Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, (1900) La Plata, Argentina
    e-mail: acorsico,althaus,obenvenu,serenell@fcaglp.fcaglp.unlp.edu.ar

(Received 7 September 2001 / Accepted 16 October 2001 )

In this letter we investigate the pulsational properties of ZZ Ceti stars on the basis of new white dwarf evolutionary models calculated in a self-consistent way with the predictions of time dependent element diffusion and nuclear burning. In addition, full account is taken of the evolutionary stages prior to the white dwarf formation. Emphasis is placed on the trapping properties of such models. By means of adiabatic, non-radial pulsation calculations, we find, as a result of time dependent diffusion, a much weaker mode trapping effect, particularly for the high-period regime of the pulsation g-spectrum. This result is valid at least for models with massive hydrogen-rich envelopes. Thus, mode trapping would not be an effective mechanism to explain the fact that all the high periods expected from standard models of stratified white dwarfs are not observed in the ZZ Ceti stars.

Key words: stars: evolution -- stars: interiors -- stars: white dwarfs -- stars: oscillations

Offprint request: A. H. Córsico, acorsico@fcaglp.unlp.edu.ar

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