Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties

Autores
Córsico, Alejandro Hugo; Althaus, Leandro Gabriel
Año de publicación
2014
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Context. Many low-mass white dwarfs with masses M∗/ M⊙ ≲ 0.45, including the so-called extremely low-mass white dwarfs (M∗/ M⊙ ≲ 0.20−0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The subsequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims. We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods. Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M⊙ derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M⊙ ZAMS star and a 1.4 M⊙ neutron star. We computed adiabatic radial (ℓ = 0) and non-radial (ℓ = 1, 2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. Results. We found that for white dwarf models with masses below ∼0.18 M⊙, g modes mainly probe the core regions and p modes the envelope, therefore pulsations offer the opportunity of constraining both the core and envelope chemical structure of these stars via asteroseismology. For models with M∗ ≳ 0.18 M⊙, on the other hand, g modes are very sensitive to the He/H compositional gradient and therefore can be used as a diagnostic tool for constraining the H envelope thickness. Because both types of objects have not only very distinct evolutionary histories (according to whether the progenitor stars have experienced CNO-flashes or not), but also have strongly different pulsation properties, we propose to define white dwarfs with masses below ∼0.18 M⊙ as ELM (extremely low-mass) white dwarfs, and white dwarfs with M∗ ≿ 0.18 M⊙ as LM (low-mass) white dwarfs.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto de Astrofísica de La Plata
Materia
Ciencias Astronómicas
asteroseismology
stars: oscillations
white dwarfs
stars: evolution
stars: interiors
stars: variables: general
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/81916

id SEDICI_512b70eee2afeb52689a647ac5cee6d0
oai_identifier_str oai:sedici.unlp.edu.ar:10915/81916
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic propertiesCórsico, Alejandro HugoAlthaus, Leandro GabrielCiencias Astronómicasasteroseismologystars: oscillationswhite dwarfsstars: evolutionstars: interiorsstars: variables: generalContext. Many low-mass white dwarfs with masses M∗/ M⊙ ≲ 0.45, including the so-called extremely low-mass white dwarfs (M∗/ M⊙ ≲ 0.20−0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The subsequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims. We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods. Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M⊙ derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M⊙ ZAMS star and a 1.4 M⊙ neutron star. We computed adiabatic radial (ℓ = 0) and non-radial (ℓ = 1, 2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. Results. We found that for white dwarf models with masses below ∼0.18 M⊙, g modes mainly probe the core regions and p modes the envelope, therefore pulsations offer the opportunity of constraining both the core and envelope chemical structure of these stars via asteroseismology. For models with M∗ ≳ 0.18 M⊙, on the other hand, g modes are very sensitive to the He/H compositional gradient and therefore can be used as a diagnostic tool for constraining the H envelope thickness. Because both types of objects have not only very distinct evolutionary histories (according to whether the progenitor stars have experienced CNO-flashes or not), but also have strongly different pulsation properties, we propose to define white dwarfs with masses below ∼0.18 M⊙ as ELM (extremely low-mass) white dwarfs, and white dwarfs with M∗ ≿ 0.18 M⊙ as LM (low-mass) white dwarfs.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plata2014info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/81916enginfo:eu-repo/semantics/altIdentifier/issn/1432-0746info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201424352info:eu-repo/semantics/reference/hdl/10915/105304info:eu-repo/semantics/reference/hdl/10915/147709info:eu-repo/semantics/reference/hdl/10915/87483info:eu-repo/semantics/reference/hdl/10915/87090info:eu-repo/semantics/reference/hdl/10915/147747info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:16Zoai:sedici.unlp.edu.ar:10915/81916Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:16.63SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
title Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
spellingShingle Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
Córsico, Alejandro Hugo
Ciencias Astronómicas
asteroseismology
stars: oscillations
white dwarfs
stars: evolution
stars: interiors
stars: variables: general
title_short Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
title_full Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
title_fullStr Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
title_full_unstemmed Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
title_sort Pulsating low-mass white dwarfs in the frame of new evolutionary sequences : I. Adiabatic properties
dc.creator.none.fl_str_mv Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author Córsico, Alejandro Hugo
author_facet Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author_role author
author2 Althaus, Leandro Gabriel
author2_role author
dc.subject.none.fl_str_mv Ciencias Astronómicas
asteroseismology
stars: oscillations
white dwarfs
stars: evolution
stars: interiors
stars: variables: general
topic Ciencias Astronómicas
asteroseismology
stars: oscillations
white dwarfs
stars: evolution
stars: interiors
stars: variables: general
dc.description.none.fl_txt_mv Context. Many low-mass white dwarfs with masses M∗/ M⊙ ≲ 0.45, including the so-called extremely low-mass white dwarfs (M∗/ M⊙ ≲ 0.20−0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The subsequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims. We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods. Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M⊙ derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M⊙ ZAMS star and a 1.4 M⊙ neutron star. We computed adiabatic radial (ℓ = 0) and non-radial (ℓ = 1, 2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. Results. We found that for white dwarf models with masses below ∼0.18 M⊙, g modes mainly probe the core regions and p modes the envelope, therefore pulsations offer the opportunity of constraining both the core and envelope chemical structure of these stars via asteroseismology. For models with M∗ ≳ 0.18 M⊙, on the other hand, g modes are very sensitive to the He/H compositional gradient and therefore can be used as a diagnostic tool for constraining the H envelope thickness. Because both types of objects have not only very distinct evolutionary histories (according to whether the progenitor stars have experienced CNO-flashes or not), but also have strongly different pulsation properties, we propose to define white dwarfs with masses below ∼0.18 M⊙ as ELM (extremely low-mass) white dwarfs, and white dwarfs with M∗ ≿ 0.18 M⊙ as LM (low-mass) white dwarfs.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto de Astrofísica de La Plata
description Context. Many low-mass white dwarfs with masses M∗/ M⊙ ≲ 0.45, including the so-called extremely low-mass white dwarfs (M∗/ M⊙ ≲ 0.20−0.25), have recently been discovered in the field of our Galaxy through dedicated photometric surveys. The subsequent discovery of pulsations in some of them has opened the unprecedented opportunity of probing the internal structure of these ancient stars. Aims. We present a detailed adiabatic pulsational study of these stars based on full evolutionary sequences derived from binary star evolution computations. The main aim of this study is to provide a detailed theoretical basis of reference for interpreting present and future observations of variable low-mass white dwarfs. Methods. Our pulsational analysis is based on a new set of He-core white-dwarf models with masses ranging from 0.1554 to 0.4352 M⊙ derived by computing the non-conservative evolution of a binary system consisting of an initially 1 M⊙ ZAMS star and a 1.4 M⊙ neutron star. We computed adiabatic radial (ℓ = 0) and non-radial (ℓ = 1, 2) p and g modes to assess the dependence of the pulsational properties of these objects on stellar parameters such as the stellar mass and the effective temperature, as well as the effects of element diffusion. Results. We found that for white dwarf models with masses below ∼0.18 M⊙, g modes mainly probe the core regions and p modes the envelope, therefore pulsations offer the opportunity of constraining both the core and envelope chemical structure of these stars via asteroseismology. For models with M∗ ≳ 0.18 M⊙, on the other hand, g modes are very sensitive to the He/H compositional gradient and therefore can be used as a diagnostic tool for constraining the H envelope thickness. Because both types of objects have not only very distinct evolutionary histories (according to whether the progenitor stars have experienced CNO-flashes or not), but also have strongly different pulsation properties, we propose to define white dwarfs with masses below ∼0.18 M⊙ as ELM (extremely low-mass) white dwarfs, and white dwarfs with M∗ ≿ 0.18 M⊙ as LM (low-mass) white dwarfs.
publishDate 2014
dc.date.none.fl_str_mv 2014
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/10915/81916
url http://sedici.unlp.edu.ar/handle/10915/81916
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/1432-0746
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201424352
info:eu-repo/semantics/reference/hdl/10915/105304
info:eu-repo/semantics/reference/hdl/10915/147709
info:eu-repo/semantics/reference/hdl/10915/87483
info:eu-repo/semantics/reference/hdl/10915/87090
info:eu-repo/semantics/reference/hdl/10915/147747
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.format.none.fl_str_mv application/pdf
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
_version_ 1844616024404525056
score 13.070432