New chemical profiles for the asteroseismology of ZZ CETI stars

We compute new chemical profiles for the core and envelope of white dwarfs appropriate for pulsational studies of ZZ Ceti stars. These profiles are extracted from the complete evolution of progenitor stars, evolved through the main sequence and the thermally pulsing asymptotic giant branch (AGB) sta...

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Autores principales: Althaus, Leandro Gabriel, Córsico, Alejandro Hugo, Bischoff-Kim, A., Romero, A.D., Renedo, I., García-Berro, E., Miller Bertolami, Marcelo Miguel
Formato: Articulo
Lenguaje:Inglés
Publicado: 2010
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Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/82496
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id I19-R120-10915-82496
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
stars: evolution
stars: interiors
stars: oscillations
white dwarfs
spellingShingle Ciencias Astronómicas
stars: evolution
stars: interiors
stars: oscillations
white dwarfs
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Bischoff-Kim, A.
Romero, A.D.
Renedo, I.
García-Berro, E.
Miller Bertolami, Marcelo Miguel
New chemical profiles for the asteroseismology of ZZ CETI stars
topic_facet Ciencias Astronómicas
stars: evolution
stars: interiors
stars: oscillations
white dwarfs
description We compute new chemical profiles for the core and envelope of white dwarfs appropriate for pulsational studies of ZZ Ceti stars. These profiles are extracted from the complete evolution of progenitor stars, evolved through the main sequence and the thermally pulsing asymptotic giant branch (AGB) stages, and from time-dependent element diffusion during white dwarf evolution. We discuss the importance of the initial-final mass relationship for the white dwarf carbon-oxygen composition. In particular, we find that the central oxygen abundance may be underestimated by about 15% if the white dwarf mass is assumed to be the hydrogen-free core mass before the first thermal pulse. We also discuss the importance for the chemical profiles expected in the outermost layers of ZZ Ceti stars of the computation of the thermally pulsing AGB phase and of the phase in which element diffusion is relevant. We find a strong dependence of the outer layer chemical stratification on the stellar mass. In particular, in the less massive models, the double-layered structure in the helium layer built up during the thermally pulsing AGB phase is not removed by diffusion by the time the ZZ Ceti stage is reached. Finally, we perform adiabatic pulsation calculations and discuss the implications of our new chemical profiles for the pulsational properties of ZZ Ceti stars. We find that the whole g-mode period spectrum and the mode-trapping properties of these pulsating white dwarfs as derived from our new chemical profiles are substantially different from those based on chemical profiles widely used in existing asteroseismological studies. Thus, we expect the asteroseismological models derived from our chemical profiles to be significantly different from those found thus far.
format Articulo
Articulo
author Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Bischoff-Kim, A.
Romero, A.D.
Renedo, I.
García-Berro, E.
Miller Bertolami, Marcelo Miguel
author_facet Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Bischoff-Kim, A.
Romero, A.D.
Renedo, I.
García-Berro, E.
Miller Bertolami, Marcelo Miguel
author_sort Althaus, Leandro Gabriel
title New chemical profiles for the asteroseismology of ZZ CETI stars
title_short New chemical profiles for the asteroseismology of ZZ CETI stars
title_full New chemical profiles for the asteroseismology of ZZ CETI stars
title_fullStr New chemical profiles for the asteroseismology of ZZ CETI stars
title_full_unstemmed New chemical profiles for the asteroseismology of ZZ CETI stars
title_sort new chemical profiles for the asteroseismology of zz ceti stars
publishDate 2010
url http://sedici.unlp.edu.ar/handle/10915/82496
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