Improved synthetic spectra of helium-core white dwarf stars

Autores
Rohrmann, René; Serenelli, Aldo Marcelo; Althaus, Leandro Gabriel; Benvenuto, Omar Gustavo
Año de publicación
2002
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability formalism. The present calculations also incorporate hydrogen-line opacity from Lyman, Balmer and Paschen series, pseudo-continuum absorptions and new updated induced-dipole absorption from H2-H2, H2-He and H-He pairs. We find that the non-ideal effects and line absorption alter the appearance of the stellar spectrum and have a significant influence upon the photometric colours in the UBVRI-JHKL system. This occurs specially for hot models Teff ≳ 8000 owing to line and pseudo-continuum opacities, and for cool models Teff ≲ 4000 where the perturbation of atoms and molecules by neighbouring particles affects the chemical equilibrium of the gas. In the present study, we also include new cooling sequences for helium-core white dwarfs of very low mass (0.160 and 0.148 M⊙) with metallicity Z = 0.02. These computations provide theoretical support to search for and identify white dwarfs of very low mass, specially useful for recent and future observational studies of globular clusters, where these objects have began to be detected.
Instituto de Astrofísica de La Plata
Materia
Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
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:10915/93539

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/93539
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Improved synthetic spectra of helium-core white dwarf starsRohrmann, RenéSerenelli, Aldo MarceloAlthaus, Leandro GabrielBenvenuto, Omar GustavoCiencias AstronómicasAtomic ProcessesStars: AtmospheresStars: EvolutionWhite DwarfsWe examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability formalism. The present calculations also incorporate hydrogen-line opacity from Lyman, Balmer and Paschen series, pseudo-continuum absorptions and new updated induced-dipole absorption from H2-H2, H2-He and H-He pairs. We find that the non-ideal effects and line absorption alter the appearance of the stellar spectrum and have a significant influence upon the photometric colours in the UBVRI-JHKL system. This occurs specially for hot models Teff ≳ 8000 owing to line and pseudo-continuum opacities, and for cool models Teff ≲ 4000 where the perturbation of atoms and molecules by neighbouring particles affects the chemical equilibrium of the gas. In the present study, we also include new cooling sequences for helium-core white dwarfs of very low mass (0.160 and 0.148 M⊙) with metallicity Z = 0.02. These computations provide theoretical support to search for and identify white dwarfs of very low mass, specially useful for recent and future observational studies of globular clusters, where these objects have began to be detected.Instituto de Astrofísica de La Plata2002-09info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf499-511http://sedici.unlp.edu.ar/handle/10915/93539enginfo:eu-repo/semantics/altIdentifier/issn/0035-8711info:eu-repo/semantics/altIdentifier/doi/10.1046/j.1365-8711.2002.05644.xinfo:eu-repo/semantics/altIdentifier/hdl/11336/36897info: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:UNLP2025-09-29T11:19:26Zoai:sedici.unlp.edu.ar:10915/93539Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:19:27.179SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Improved synthetic spectra of helium-core white dwarf stars
title Improved synthetic spectra of helium-core white dwarf stars
spellingShingle Improved synthetic spectra of helium-core white dwarf stars
Rohrmann, René
Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
title_short Improved synthetic spectra of helium-core white dwarf stars
title_full Improved synthetic spectra of helium-core white dwarf stars
title_fullStr Improved synthetic spectra of helium-core white dwarf stars
title_full_unstemmed Improved synthetic spectra of helium-core white dwarf stars
title_sort Improved synthetic spectra of helium-core white dwarf stars
dc.creator.none.fl_str_mv Rohrmann, René
Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
author Rohrmann, René
author_facet Rohrmann, René
Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
author_role author
author2 Serenelli, Aldo Marcelo
Althaus, Leandro Gabriel
Benvenuto, Omar Gustavo
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
topic Ciencias Astronómicas
Atomic Processes
Stars: Atmospheres
Stars: Evolution
White Dwarfs
dc.description.none.fl_txt_mv We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability formalism. The present calculations also incorporate hydrogen-line opacity from Lyman, Balmer and Paschen series, pseudo-continuum absorptions and new updated induced-dipole absorption from H2-H2, H2-He and H-He pairs. We find that the non-ideal effects and line absorption alter the appearance of the stellar spectrum and have a significant influence upon the photometric colours in the UBVRI-JHKL system. This occurs specially for hot models Teff ≳ 8000 owing to line and pseudo-continuum opacities, and for cool models Teff ≲ 4000 where the perturbation of atoms and molecules by neighbouring particles affects the chemical equilibrium of the gas. In the present study, we also include new cooling sequences for helium-core white dwarfs of very low mass (0.160 and 0.148 M⊙) with metallicity Z = 0.02. These computations provide theoretical support to search for and identify white dwarfs of very low mass, specially useful for recent and future observational studies of globular clusters, where these objects have began to be detected.
Instituto de Astrofísica de La Plata
description We examine the emergent fluxes from helium-core white dwarfs following their evolution from the end of pre-white dwarf stages down to advanced cooling stages. For this purpose, we include a detailed treatment of the physics of the atmosphere, particularly an improved representation of the state of the gas by taking into account non-ideal effects according to the so-called occupation probability formalism. The present calculations also incorporate hydrogen-line opacity from Lyman, Balmer and Paschen series, pseudo-continuum absorptions and new updated induced-dipole absorption from H2-H2, H2-He and H-He pairs. We find that the non-ideal effects and line absorption alter the appearance of the stellar spectrum and have a significant influence upon the photometric colours in the UBVRI-JHKL system. This occurs specially for hot models Teff ≳ 8000 owing to line and pseudo-continuum opacities, and for cool models Teff ≲ 4000 where the perturbation of atoms and molecules by neighbouring particles affects the chemical equilibrium of the gas. In the present study, we also include new cooling sequences for helium-core white dwarfs of very low mass (0.160 and 0.148 M⊙) with metallicity Z = 0.02. These computations provide theoretical support to search for and identify white dwarfs of very low mass, specially useful for recent and future observational studies of globular clusters, where these objects have began to be detected.
publishDate 2002
dc.date.none.fl_str_mv 2002-09
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/10915/93539
url http://sedici.unlp.edu.ar/handle/10915/93539
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.1365-8711.2002.05644.x
info:eu-repo/semantics/altIdentifier/hdl/11336/36897
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
499-511
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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