Gravitational settling of 22Ne and white dwarf evolution

We study the effects of the sedimentation of the trace element <SUP>22</SUP>Ne in the cooling of white dwarfs. In contrast with previous studies - which adopted a simplified treatment of the effects of <SUP>22</SUP>Ne sedimentation - this is done self-consistently for the fir...

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Detalles Bibliográficos
Autores principales: García Berro, E., Althaus, Leandro Gabriel, Córsico, Alejandro Hugo, Isern, J.
Formato: Articulo
Lenguaje:Inglés
Publicado: 2008
Materias:
Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/84174
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-84174
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
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
spellingShingle Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
García Berro, E.
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
Gravitational settling of 22Ne and white dwarf evolution
topic_facet Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
description We study the effects of the sedimentation of the trace element <SUP>22</SUP>Ne in the cooling of white dwarfs. In contrast with previous studies - which adopted a simplified treatment of the effects of <SUP>22</SUP>Ne sedimentation - this is done self-consistently for the first time, using an up-to-date stellar evolutionary code in which the diffusion equation is coupled with the full set of equations of stellar evolution. Due the large neutron excess of <SUP>22</SUP>Ne, this isotope rapidly sediments in the interior of the white dwarf. Although we explore a wide range of parameters, we find that when using the most reasonable assumptions concerning the diffusion coefficient and the physical state of the white dwarf interior, the delay introduced by the ensuing chemical differentiation is minor for a typical 0.6 M⊙ white dwarf. For more massive white dwarfs, say M<SUB>WD</SUB> ∼1.0 M ⊙, the delay turns out to be considerably larger. These results are in qualitatively good accord with those obtained in previous studies, but we find that the magnitude of the delay introduced by <SUP>22</SUP>Ne sedimentation was underestimated by a factor of ∼2. We also perform a preliminary study of the impact of <SUP>22</SUP>Ne sedimentation on the white dwarf luminosity function. Finally, we hypothesize on the possibility of detecting the sedimentation of <SUP>22</SUP>Ne using pulsating white dwarfs in the appropriate effective temperature range with accurately determined rates of change of the observed periods.
format Articulo
Articulo
author García Berro, E.
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
author_facet García Berro, E.
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
author_sort García Berro, E.
title Gravitational settling of 22Ne and white dwarf evolution
title_short Gravitational settling of 22Ne and white dwarf evolution
title_full Gravitational settling of 22Ne and white dwarf evolution
title_fullStr Gravitational settling of 22Ne and white dwarf evolution
title_full_unstemmed Gravitational settling of 22Ne and white dwarf evolution
title_sort gravitational settling of 22ne and white dwarf evolution
publishDate 2008
url http://sedici.unlp.edu.ar/handle/10915/84174
work_keys_str_mv AT garciaberroe gravitationalsettlingof22neandwhitedwarfevolution
AT althausleandrogabriel gravitationalsettlingof22neandwhitedwarfevolution
AT corsicoalejandrohugo gravitationalsettlingof22neandwhitedwarfevolution
AT isernj gravitationalsettlingof22neandwhitedwarfevolution
bdutipo_str Repositorios
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