Gravitational settling of 22Ne and white dwarf evolution

Autores
García Berro, E.; Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Isern, J.
Año de publicación
2008
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We study the effects of the sedimentation of the trace element 22Ne in the cooling of white dwarfs. In contrast with previous studies - which adopted a simplified treatment of the effects of 22Ne 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 22Ne, 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 MWD ∼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 22Ne sedimentation was underestimated by a factor of ∼2. We also perform a preliminary study of the impact of 22Ne sedimentation on the white dwarf luminosity function. Finally, we hypothesize on the possibility of detecting the sedimentation of 22Ne using pulsating white dwarfs in the appropriate effective temperature range with accurately determined rates of change of the observed periods.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/84174

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/84174
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Gravitational settling of 22Ne and white dwarf evolutionGarcía Berro, E.Althaus, Leandro GabrielCórsico, Alejandro HugoIsern, J.Ciencias AstronómicasDense matterDiffusionStars: abundancesStars: evolutionStars: interiorsWhite dwarfsWe 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.Facultad de Ciencias Astronómicas y Geofísicas2008info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf473-482http://sedici.unlp.edu.ar/handle/10915/84174enginfo:eu-repo/semantics/altIdentifier/issn/0004-637Xinfo:eu-repo/semantics/altIdentifier/doi/10.1086/527536info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:16:14Zoai:sedici.unlp.edu.ar:10915/84174Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:16:15.17SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Gravitational settling of 22Ne and white dwarf evolution
title Gravitational settling of 22Ne and white dwarf evolution
spellingShingle Gravitational settling of 22Ne and white dwarf evolution
García Berro, E.
Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
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
dc.creator.none.fl_str_mv García Berro, E.
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
author García Berro, E.
author_facet García Berro, E.
Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
author_role author
author2 Althaus, Leandro Gabriel
Córsico, Alejandro Hugo
Isern, J.
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
topic Ciencias Astronómicas
Dense matter
Diffusion
Stars: abundances
Stars: evolution
Stars: interiors
White dwarfs
dc.description.none.fl_txt_mv 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.
Facultad de Ciencias Astronómicas y Geofísicas
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.
publishDate 2008
dc.date.none.fl_str_mv 2008
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/84174
url http://sedici.unlp.edu.ar/handle/10915/84174
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004-637X
info:eu-repo/semantics/altIdentifier/doi/10.1086/527536
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
473-482
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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