Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A

Autores
Benvenuto, Omar Gustavo; Córsico, Alejandro Hugo; Althaus, Leandro Gabriel; Serenelli, Aldo Marcelo
Año de publicación
2002
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We study the structural characteristic of the variable DA white dwarf G117-B15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical description as well as several processes responsible for the occurrence of element diffusion. We have considered several thicknesses for the outermost hydrogen layer, whereas for the inner helium-, carbon- and oxygen-rich layers we considered realistic profiles predicted by calculations of the white dwarf progenitor evolution. The stellar masses we have analysed cover the mass range of 0.50 ≤ M⁎/M⊙ ≤ 0.60. The evolution of each of the considered model sequences was followed down to very low effective temperatures; in particular, from 12 500 K on we computed the dipolar, linear, adiabatic oscillations with radial order k = 1,..., 4. We find that asteroseismological results are not univocal regarding mode identification for the case of G117-B15A. However, our asteroseismological results are compatible with spectroscopic data only if the observed periods of 215.2, 271.0 and 304.4 s are due to dipolar modes with k = 2, 3, 4, respectively. Our calculations indicate that the best fit to the observed period pattern of G117-B15A corresponds to a DA white dwarf structure with a stellar mass of 0.525 M⊙, with a hydrogen mass fraction log(MH/M⁎) ≳ -3.83 at an effective temperature Teff ≈ 11 800 K. The value of the stellar mass is consistent with that obtained spectroscopically by Koester & Allard.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Stars: evolution
Stars: individual: G117-B15A
Stars: interiors
Stars: oscillations
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:10915/84613
Acceder
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oai_identifier_str oai:sedici.unlp.edu.ar:10915/84613
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15ABenvenuto, Omar GustavoCórsico, Alejandro HugoAlthaus, Leandro GabrielSerenelli, Aldo MarceloCiencias AstronómicasStars: evolutionStars: individual: G117-B15AStars: interiorsStars: oscillationsWhite dwarfsWe study the structural characteristic of the variable DA white dwarf G117-B15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical description as well as several processes responsible for the occurrence of element diffusion. We have considered several thicknesses for the outermost hydrogen layer, whereas for the inner helium-, carbon- and oxygen-rich layers we considered realistic profiles predicted by calculations of the white dwarf progenitor evolution. The stellar masses we have analysed cover the mass range of 0.50 ≤ M⁎/M⊙ ≤ 0.60. The evolution of each of the considered model sequences was followed down to very low effective temperatures; in particular, from 12 500 K on we computed the dipolar, linear, adiabatic oscillations with radial order k = 1,..., 4. We find that asteroseismological results are not univocal regarding mode identification for the case of G117-B15A. However, our asteroseismological results are compatible with spectroscopic data only if the observed periods of 215.2, 271.0 and 304.4 s are due to dipolar modes with k = 2, 3, 4, respectively. Our calculations indicate that the best fit to the observed period pattern of G117-B15A corresponds to a DA white dwarf structure with a stellar mass of 0.525 M⊙, with a hydrogen mass fraction log(M<SUB>H</SUB>/M⁎) ≳ -3.83 at an effective temperature T<SUB>eff</SUB> ≈ 11 800 K. The value of the stellar mass is consistent with that obtained spectroscopically by Koester & Allard.Facultad de Ciencias Astronómicas y Geofísicas2002info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf399-408http://sedici.unlp.edu.ar/handle/10915/84613enginfo:eu-repo/semantics/altIdentifier/issn/0035-8711info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-8711.2002.05312.xinfo: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:UNLP2025-10-22T16:57:07Zoai:sedici.unlp.edu.ar:10915/84613Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-10-22 16:57:07.834SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
title Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
spellingShingle Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
Benvenuto, Omar Gustavo
Ciencias Astronómicas
Stars: evolution
Stars: individual: G117-B15A
Stars: interiors
Stars: oscillations
White dwarfs
title_short Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
title_full Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
title_fullStr Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
title_full_unstemmed Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
title_sort Time-dependent diffusion in pulsating white dwarf stars: Asteroseismology of G117-B15A
dc.creator.none.fl_str_mv Benvenuto, Omar Gustavo
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
Serenelli, Aldo Marcelo
author Benvenuto, Omar Gustavo
author_facet Benvenuto, Omar Gustavo
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
Serenelli, Aldo Marcelo
author_role author
author2 Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
Serenelli, Aldo Marcelo
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Stars: evolution
Stars: individual: G117-B15A
Stars: interiors
Stars: oscillations
White dwarfs
topic Ciencias Astronómicas
Stars: evolution
Stars: individual: G117-B15A
Stars: interiors
Stars: oscillations
White dwarfs
dc.description.none.fl_txt_mv We study the structural characteristic of the variable DA white dwarf G117-B15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical description as well as several processes responsible for the occurrence of element diffusion. We have considered several thicknesses for the outermost hydrogen layer, whereas for the inner helium-, carbon- and oxygen-rich layers we considered realistic profiles predicted by calculations of the white dwarf progenitor evolution. The stellar masses we have analysed cover the mass range of 0.50 ≤ M⁎/M⊙ ≤ 0.60. The evolution of each of the considered model sequences was followed down to very low effective temperatures; in particular, from 12 500 K on we computed the dipolar, linear, adiabatic oscillations with radial order k = 1,..., 4. We find that asteroseismological results are not univocal regarding mode identification for the case of G117-B15A. However, our asteroseismological results are compatible with spectroscopic data only if the observed periods of 215.2, 271.0 and 304.4 s are due to dipolar modes with k = 2, 3, 4, respectively. Our calculations indicate that the best fit to the observed period pattern of G117-B15A corresponds to a DA white dwarf structure with a stellar mass of 0.525 M⊙, with a hydrogen mass fraction log(M<SUB>H</SUB>/M⁎) ≳ -3.83 at an effective temperature T<SUB>eff</SUB> ≈ 11 800 K. The value of the stellar mass is consistent with that obtained spectroscopically by Koester & Allard.
Facultad de Ciencias Astronómicas y Geofísicas
description We study the structural characteristic of the variable DA white dwarf G117-B15A by applying the methods of asteroseismology. For such a purpose, we construct white dwarf evolutionary models considering a detailed and up-to-date physical description as well as several processes responsible for the occurrence of element diffusion. We have considered several thicknesses for the outermost hydrogen layer, whereas for the inner helium-, carbon- and oxygen-rich layers we considered realistic profiles predicted by calculations of the white dwarf progenitor evolution. The stellar masses we have analysed cover the mass range of 0.50 ≤ M⁎/M⊙ ≤ 0.60. The evolution of each of the considered model sequences was followed down to very low effective temperatures; in particular, from 12 500 K on we computed the dipolar, linear, adiabatic oscillations with radial order k = 1,..., 4. We find that asteroseismological results are not univocal regarding mode identification for the case of G117-B15A. However, our asteroseismological results are compatible with spectroscopic data only if the observed periods of 215.2, 271.0 and 304.4 s are due to dipolar modes with k = 2, 3, 4, respectively. Our calculations indicate that the best fit to the observed period pattern of G117-B15A corresponds to a DA white dwarf structure with a stellar mass of 0.525 M⊙, with a hydrogen mass fraction log(M<SUB>H</SUB>/M⁎) ≳ -3.83 at an effective temperature T<SUB>eff</SUB> ≈ 11 800 K. The value of the stellar mass is consistent with that obtained spectroscopically by Koester & Allard.
publishDate 2002
dc.date.none.fl_str_mv 2002
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/10915/84613
url http://sedici.unlp.edu.ar/handle/10915/84613
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0035-8711
info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-8711.2002.05312.x
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
399-408
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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