The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties

Context. The existence of ultra-massive white dwarf stars, M & 1.05 M, has been reported in several studies. These white dwarfs are relevant for the role they play in type Ia supernova explosions, the occurrence of physical processes in the asymptotic giant-branch phase, the existence of high-fi...

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Autores: Althaus, Leandro G., Gil Pons, Pilar, Córsico, Alejandro H., Miller Bertolami, Marcelo M., Gerónimo, Francisco de, Camisassa, María E., Torres, Santiago, Gutiérrez, Jordi, Rebassa-Mansergas, Alberto
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2021
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/249717
Acceso en línea:http://hdl.handle.net/10261/249717
Access Level:acceso abierto
Palabra clave:Stars: evolution
Stars: interiors
White dwarfs
Stars: oscillations
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repository_id_str
spelling The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational propertiesAlthaus, Leandro G.Gil Pons, PilarCórsico, Alejandro H.Miller Bertolami, Marcelo M.Gerónimo, Francisco deCamisassa, María E.Torres, SantiagoGutiérrez, JordiRebassa-Mansergas, AlbertoStars: evolutionStars: interiorsWhite dwarfsStars: oscillationsContext. The existence of ultra-massive white dwarf stars, M & 1.05 M, has been reported in several studies. These white dwarfs are relevant for the role they play in type Ia supernova explosions, the occurrence of physical processes in the asymptotic giant-branch phase, the existence of high-field magnetic white dwarfs, and the occurrence of double-white-dwarf mergers. Aims. We aim to explore the formation of ultra-massive, carbon-oxygen core white dwarfs resulting from single stellar evolution. We also intend to study their evolutionary and pulsational properties and compare them with those of the ultra-massive white dwarfs with oxygen-neon cores resulting from carbon burning in single progenitor stars, and with binary merger predictions. The aim is to provide a theoretical basis that can eventually help to discern the core composition of ultra-massive white dwarfs and the circumstances of their formation. Methods. We considered two single-star evolution scenarios for the formation of ultra-massive carbon-oxygen core white dwarfs, which involve the rotation of the degenerate core after core helium burning and reduced mass-loss rates in massive asymptotic giant-branch stars. We find that reducing standard mass-loss rates by a factor larger than 5−20 yields the formation of carbon-oxygen cores more massive than 1.05 M as a result of the slow growth of carbon-oxygen core mass during the thermal pulses. We also performed a series of evolutionary tests of solar-metallicity models with initial masses between 4 and 9.5 M and with different core rotation rates. We find that ultra-massive carbon-oxygen core white dwarfs are formed even for the lowest rotation rates we analyzed, and that the range of initial masses leading to these white dwarfs widens as the rotation rate of the core increases, whereas the initial mass range for the formation of oxygen-neon core white dwarfs decreases significantly. Finally, we compared our findings with the predictions from ultra-massive white dwarfs resulting from the merger of two equal-mass carbon-oxygen core white dwarfs, by assuming complete mixing between them and a carbon-oxygen core for the merged remnant. Results. These two single-evolution scenarios produce ultra-massive white dwarfs with different carbon-oxygen profiles and different helium contents, thus leading to distinctive signatures in the period spectrum and mode-trapping properties of pulsating hydrogen-rich white dwarfs. The resulting ultra-massive carbon-oxygen core white dwarfs evolve markedly slower than their oxygen-neon counterparts. Conclusions. Our study strongly suggests the formation of ultra-massive white dwarfs with carbon-oxygen cores from a single stellar evolution. We find that both the evolutionary and pulsation properties of these white dwarfs are markedly different from those of their oxygen-neon core counterparts and from those white dwarfs with carbon-oxygen cores that might result from double-degenerate mergers. This can eventually be used to discern the core composition of ultra-massive white dwarfs and their formation scenario.Peer reviewedEDP SciencesConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2021202120212021info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/249717reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Ingléshttp://doi.org/10.1051/0004-6361/202038930Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/2497172026-05-22T06:33:51Z
dc.title.none.fl_str_mv The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
title The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
spellingShingle The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
Althaus, Leandro G.
Stars: evolution
Stars: interiors
White dwarfs
Stars: oscillations
title_short The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
title_full The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
title_fullStr The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
title_full_unstemmed The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
title_sort The formation of ultra-massive carbon-oxygen core white dwarfs and their evolutionary and pulsational properties
dc.creator.none.fl_str_mv Althaus, Leandro G.
Gil Pons, Pilar
Córsico, Alejandro H.
Miller Bertolami, Marcelo M.
Gerónimo, Francisco de
Camisassa, María E.
Torres, Santiago
Gutiérrez, Jordi
Rebassa-Mansergas, Alberto
author Althaus, Leandro G.
author_facet Althaus, Leandro G.
Gil Pons, Pilar
Córsico, Alejandro H.
Miller Bertolami, Marcelo M.
Gerónimo, Francisco de
Camisassa, María E.
Torres, Santiago
Gutiérrez, Jordi
Rebassa-Mansergas, Alberto
author_role author
author2 Gil Pons, Pilar
Córsico, Alejandro H.
Miller Bertolami, Marcelo M.
Gerónimo, Francisco de
Camisassa, María E.
Torres, Santiago
Gutiérrez, Jordi
Rebassa-Mansergas, Alberto
author2_role author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Stars: evolution
Stars: interiors
White dwarfs
Stars: oscillations
topic Stars: evolution
Stars: interiors
White dwarfs
Stars: oscillations
description Context. The existence of ultra-massive white dwarf stars, M & 1.05 M, has been reported in several studies. These white dwarfs are relevant for the role they play in type Ia supernova explosions, the occurrence of physical processes in the asymptotic giant-branch phase, the existence of high-field magnetic white dwarfs, and the occurrence of double-white-dwarf mergers. Aims. We aim to explore the formation of ultra-massive, carbon-oxygen core white dwarfs resulting from single stellar evolution. We also intend to study their evolutionary and pulsational properties and compare them with those of the ultra-massive white dwarfs with oxygen-neon cores resulting from carbon burning in single progenitor stars, and with binary merger predictions. The aim is to provide a theoretical basis that can eventually help to discern the core composition of ultra-massive white dwarfs and the circumstances of their formation. Methods. We considered two single-star evolution scenarios for the formation of ultra-massive carbon-oxygen core white dwarfs, which involve the rotation of the degenerate core after core helium burning and reduced mass-loss rates in massive asymptotic giant-branch stars. We find that reducing standard mass-loss rates by a factor larger than 5−20 yields the formation of carbon-oxygen cores more massive than 1.05 M as a result of the slow growth of carbon-oxygen core mass during the thermal pulses. We also performed a series of evolutionary tests of solar-metallicity models with initial masses between 4 and 9.5 M and with different core rotation rates. We find that ultra-massive carbon-oxygen core white dwarfs are formed even for the lowest rotation rates we analyzed, and that the range of initial masses leading to these white dwarfs widens as the rotation rate of the core increases, whereas the initial mass range for the formation of oxygen-neon core white dwarfs decreases significantly. Finally, we compared our findings with the predictions from ultra-massive white dwarfs resulting from the merger of two equal-mass carbon-oxygen core white dwarfs, by assuming complete mixing between them and a carbon-oxygen core for the merged remnant. Results. These two single-evolution scenarios produce ultra-massive white dwarfs with different carbon-oxygen profiles and different helium contents, thus leading to distinctive signatures in the period spectrum and mode-trapping properties of pulsating hydrogen-rich white dwarfs. The resulting ultra-massive carbon-oxygen core white dwarfs evolve markedly slower than their oxygen-neon counterparts. Conclusions. Our study strongly suggests the formation of ultra-massive white dwarfs with carbon-oxygen cores from a single stellar evolution. We find that both the evolutionary and pulsation properties of these white dwarfs are markedly different from those of their oxygen-neon core counterparts and from those white dwarfs with carbon-oxygen cores that might result from double-degenerate mergers. This can eventually be used to discern the core composition of ultra-massive white dwarfs and their formation scenario.
publishDate 2021
dc.date.none.fl_str_mv 2021
2021
2021
2021
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/249717
url http://hdl.handle.net/10261/249717
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv http://doi.org/10.1051/0004-6361/202038930
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,811543

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