Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion

Autores
Althaus, Leandro Gabriel; García Berro, E.; Renedo, I.; Isern, J.; Córsico, Alejandro Hugo; Rohrmann, René
Año de publicación
2010
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Motivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of 22Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0M⊙, and is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that 22Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, while carbon/oxygen phase separation adds considerable delays at lowluminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of 22Ne. Changing the diffusion coefficient by a factor of 2 leads to maximum age differences of ≈8%-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slowdown in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.
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:10915/82514

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network_name_str SEDICI (UNLP)
spelling Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusionAlthaus, Leandro GabrielGarcía Berro, E.Renedo, I.Isern, J.Córsico, Alejandro HugoRohrmann, RenéCiencias AstronómicasDense matterDiffusionStars: AbundancesStars: EvolutionStars: InteriorsWhite dwarfsMotivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of <SUP>22</SUP>Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0M⊙, and is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that <SUP>22</SUP>Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, while carbon/oxygen phase separation adds considerable delays at lowluminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of <SUP>22</SUP>Ne. Changing the diffusion coefficient by a factor of 2 leads to maximum age differences of ≈8%-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slowdown in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.Facultad de Ciencias Astronómicas y Geofísicas2010info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf612-621http://sedici.unlp.edu.ar/handle/10915/82514enginfo:eu-repo/semantics/altIdentifier/issn/0004637Xinfo:eu-repo/semantics/altIdentifier/doi/10.1088/0004-637X/719/1/612info: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:UNLP2025-09-29T11:15:31Zoai:sedici.unlp.edu.ar:10915/82514Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:31.209SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
spellingShingle Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
Althaus, Leandro Gabriel
Ciencias Astronómicas
Dense matter
Diffusion
Stars: Abundances
Stars: Evolution
Stars: Interiors
White dwarfs
title_short Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_full Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_fullStr Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_full_unstemmed Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
title_sort Evolution of white dwarf stars with high-metallicity progenitors: The role of 22Ne diffusion
dc.creator.none.fl_str_mv Althaus, Leandro Gabriel
García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
author Althaus, Leandro Gabriel
author_facet Althaus, Leandro Gabriel
García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
author_role author
author2 García Berro, E.
Renedo, I.
Isern, J.
Córsico, Alejandro Hugo
Rohrmann, René
author2_role author
author
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 Motivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of <SUP>22</SUP>Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0M⊙, and is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that <SUP>22</SUP>Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, while carbon/oxygen phase separation adds considerable delays at lowluminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of <SUP>22</SUP>Ne. Changing the diffusion coefficient by a factor of 2 leads to maximum age differences of ≈8%-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slowdown in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.
Facultad de Ciencias Astronómicas y Geofísicas
description Motivated by the strong discrepancy between the main-sequence turnoff age and the white dwarf cooling age in the metal-rich open cluster NGC 6791, we compute a grid of white dwarf evolutionary sequences that incorporates for the first time the energy released by the processes of <SUP>22</SUP>Ne sedimentation and of carbon/oxygen phase separation upon crystallization. The grid covers the mass range from 0.52 to 1.0M⊙, and is appropriate for the study of white dwarfs in metal-rich clusters. The evolutionary calculations are based on a detailed and self-consistent treatment of the energy released from these two processes, as well as on the employment of realistic carbon/oxygen profiles, of relevance for an accurate evaluation of the energy released by carbon/oxygen phase separation. We find that <SUP>22</SUP>Ne sedimentation strongly delays the cooling rate of white dwarfs stemming from progenitors with high metallicities at moderate luminosities, while carbon/oxygen phase separation adds considerable delays at lowluminosities. Cooling times are sensitive to possible uncertainties in the actual value of the diffusion coefficient of <SUP>22</SUP>Ne. Changing the diffusion coefficient by a factor of 2 leads to maximum age differences of ≈8%-20% depending on the stellar mass. We find that the magnitude of the delays resulting from chemical changes in the core is consistent with the slowdown in the white dwarf cooling rate that is required to solve the age discrepancy in NGC 6791.
publishDate 2010
dc.date.none.fl_str_mv 2010
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/10915/82514
url http://sedici.unlp.edu.ar/handle/10915/82514
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004637X
info:eu-repo/semantics/altIdentifier/doi/10.1088/0004-637X/719/1/612
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
612-621
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
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instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
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