A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation

Autores
Camisassa, Maria; Torres, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; Althaus, Leandro Gabriel; Rebassa Mansergas, Alberto
Año de publicación
2023
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the A branch consists mostly of white dwarfs with hydrogen(H)-rich atmospheres, the B branch is not completely understood. Although it has been proposed that the B branch is populated mainly by helium (He)-rich white dwarfs, this branch overlaps with a â ¼0.8â Mâ evolutionary track with a pure He envelope, which would imply an unexpected peak in the white dwarf mass distribution. Aims. In cold He-rich white dwarfs, it is expected that the outer convective zone penetrates into deep carbon (C) -rich layers, leading to a slight C contamination in their surfaces at â ¼10â 000 K. In this paper we aim to study the Gaia bifurcation as the natural consequence of C dredge-up by convection in cold He-dominated white dwarfs. Methods. Relying on accurate atmosphere models, we provide a new set of evolutionary models for He-rich white dwarfs, which employ different prescriptions for the C enrichment. On the basis of these models, we carried out a population synthesis study of the Gaia 100 pc white dwarf sample to constrain the models that best fit the bifurcation. Results. Our study shows that He-rich white dwarf models with a slight C contamination below the optical detection limit can accurately reproduce the Gaia bifurcation. We refer to these stars as â stealth DQâ white dwarfs because they do not exhibit detectable C signatures in their optical spectra, but the presence of C in their atmosphere produces a continuum absorption favoring the emission in bluer wavelengths, thereby creating the B branch of the bifurcation. Furthermore, our study shows that the white dwarf mass distribution obtained when a stealth C contamination is taken into account presents a peak at â ¼0.6â Mâ , which is consistent with the mass distribution for H-rich white dwarfs and with the standard evolutionary channels for their formation. Conclusions. We conclude that stealth DQ white dwarfs can account for the lower branch in the Gaia bifurcation. The C signatures of these stars could be detectable in ultraviolet (UV) spectra.
Fil: Camisassa, Maria. Universidad Politécnica de Catalunya; España
Fil: Torres, Santiago. Universidad Politécnica de Catalunya; España
Fil: Hollands, Mark. Universidad Politécnica de Catalunya; España
Fil: Koester, Detlev. Christian Albrechts Universitat Zu Kiel; Alemania
Fil: Raddi, Roberto. Universidad Politécnica de Catalunya; España
Fil: Althaus, Leandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina
Fil: Rebassa Mansergas, Alberto. Universidad Politécnica de Catalunya; España
Materia
STARS: ATMOSPHERES
STARS: EVOLUTION
STARS: INTERIORS
WHITE DWARFS
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/218790

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network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcationCamisassa, MariaTorres, SantiagoHollands, MarkKoester, DetlevRaddi, RobertoAlthaus, Leandro GabrielRebassa Mansergas, AlbertoSTARS: ATMOSPHERESSTARS: EVOLUTIONSTARS: INTERIORSWHITE DWARFShttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the A branch consists mostly of white dwarfs with hydrogen(H)-rich atmospheres, the B branch is not completely understood. Although it has been proposed that the B branch is populated mainly by helium (He)-rich white dwarfs, this branch overlaps with a â ¼0.8â Mâ evolutionary track with a pure He envelope, which would imply an unexpected peak in the white dwarf mass distribution. Aims. In cold He-rich white dwarfs, it is expected that the outer convective zone penetrates into deep carbon (C) -rich layers, leading to a slight C contamination in their surfaces at â ¼10â 000 K. In this paper we aim to study the Gaia bifurcation as the natural consequence of C dredge-up by convection in cold He-dominated white dwarfs. Methods. Relying on accurate atmosphere models, we provide a new set of evolutionary models for He-rich white dwarfs, which employ different prescriptions for the C enrichment. On the basis of these models, we carried out a population synthesis study of the Gaia 100 pc white dwarf sample to constrain the models that best fit the bifurcation. Results. Our study shows that He-rich white dwarf models with a slight C contamination below the optical detection limit can accurately reproduce the Gaia bifurcation. We refer to these stars as â stealth DQâ white dwarfs because they do not exhibit detectable C signatures in their optical spectra, but the presence of C in their atmosphere produces a continuum absorption favoring the emission in bluer wavelengths, thereby creating the B branch of the bifurcation. Furthermore, our study shows that the white dwarf mass distribution obtained when a stealth C contamination is taken into account presents a peak at â ¼0.6â Mâ , which is consistent with the mass distribution for H-rich white dwarfs and with the standard evolutionary channels for their formation. Conclusions. We conclude that stealth DQ white dwarfs can account for the lower branch in the Gaia bifurcation. The C signatures of these stars could be detectable in ultraviolet (UV) spectra.Fil: Camisassa, Maria. Universidad Politécnica de Catalunya; EspañaFil: Torres, Santiago. Universidad Politécnica de Catalunya; EspañaFil: Hollands, Mark. Universidad Politécnica de Catalunya; EspañaFil: Koester, Detlev. Christian Albrechts Universitat Zu Kiel; AlemaniaFil: Raddi, Roberto. Universidad Politécnica de Catalunya; EspañaFil: Althaus, Leandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Rebassa Mansergas, Alberto. Universidad Politécnica de Catalunya; EspañaEDP Sciences2023-06info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/218790Camisassa, Maria; Torres, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; et al.; A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation; EDP Sciences; Astronomy and Astrophysics; 674; A213; 6-2023; 1-90004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/10.1051/0004-6361/202346628info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/202346628info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T09:47:05Zoai:ri.conicet.gov.ar:11336/218790instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 09:47:05.498CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
title A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
spellingShingle A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
Camisassa, Maria
STARS: ATMOSPHERES
STARS: EVOLUTION
STARS: INTERIORS
WHITE DWARFS
title_short A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
title_full A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
title_fullStr A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
title_full_unstemmed A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
title_sort A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation
dc.creator.none.fl_str_mv Camisassa, Maria
Torres, Santiago
Hollands, Mark
Koester, Detlev
Raddi, Roberto
Althaus, Leandro Gabriel
Rebassa Mansergas, Alberto
author Camisassa, Maria
author_facet Camisassa, Maria
Torres, Santiago
Hollands, Mark
Koester, Detlev
Raddi, Roberto
Althaus, Leandro Gabriel
Rebassa Mansergas, Alberto
author_role author
author2 Torres, Santiago
Hollands, Mark
Koester, Detlev
Raddi, Roberto
Althaus, Leandro Gabriel
Rebassa Mansergas, Alberto
author2_role author
author
author
author
author
author
dc.subject.none.fl_str_mv STARS: ATMOSPHERES
STARS: EVOLUTION
STARS: INTERIORS
WHITE DWARFS
topic STARS: ATMOSPHERES
STARS: EVOLUTION
STARS: INTERIORS
WHITE DWARFS
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the A branch consists mostly of white dwarfs with hydrogen(H)-rich atmospheres, the B branch is not completely understood. Although it has been proposed that the B branch is populated mainly by helium (He)-rich white dwarfs, this branch overlaps with a â ¼0.8â Mâ evolutionary track with a pure He envelope, which would imply an unexpected peak in the white dwarf mass distribution. Aims. In cold He-rich white dwarfs, it is expected that the outer convective zone penetrates into deep carbon (C) -rich layers, leading to a slight C contamination in their surfaces at â ¼10â 000 K. In this paper we aim to study the Gaia bifurcation as the natural consequence of C dredge-up by convection in cold He-dominated white dwarfs. Methods. Relying on accurate atmosphere models, we provide a new set of evolutionary models for He-rich white dwarfs, which employ different prescriptions for the C enrichment. On the basis of these models, we carried out a population synthesis study of the Gaia 100 pc white dwarf sample to constrain the models that best fit the bifurcation. Results. Our study shows that He-rich white dwarf models with a slight C contamination below the optical detection limit can accurately reproduce the Gaia bifurcation. We refer to these stars as â stealth DQâ white dwarfs because they do not exhibit detectable C signatures in their optical spectra, but the presence of C in their atmosphere produces a continuum absorption favoring the emission in bluer wavelengths, thereby creating the B branch of the bifurcation. Furthermore, our study shows that the white dwarf mass distribution obtained when a stealth C contamination is taken into account presents a peak at â ¼0.6â Mâ , which is consistent with the mass distribution for H-rich white dwarfs and with the standard evolutionary channels for their formation. Conclusions. We conclude that stealth DQ white dwarfs can account for the lower branch in the Gaia bifurcation. The C signatures of these stars could be detectable in ultraviolet (UV) spectra.
Fil: Camisassa, Maria. Universidad Politécnica de Catalunya; España
Fil: Torres, Santiago. Universidad Politécnica de Catalunya; España
Fil: Hollands, Mark. Universidad Politécnica de Catalunya; España
Fil: Koester, Detlev. Christian Albrechts Universitat Zu Kiel; Alemania
Fil: Raddi, Roberto. Universidad Politécnica de Catalunya; España
Fil: Althaus, Leandro Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina
Fil: Rebassa Mansergas, Alberto. Universidad Politécnica de Catalunya; España
description Context. The high-quality photometric and astrometric capabilities of the ESA Gaia space mission have revealed a bifurcation of the white dwarf sequence on the color magnitude diagram with two branches: A and B. While the A branch consists mostly of white dwarfs with hydrogen(H)-rich atmospheres, the B branch is not completely understood. Although it has been proposed that the B branch is populated mainly by helium (He)-rich white dwarfs, this branch overlaps with a â ¼0.8â Mâ evolutionary track with a pure He envelope, which would imply an unexpected peak in the white dwarf mass distribution. Aims. In cold He-rich white dwarfs, it is expected that the outer convective zone penetrates into deep carbon (C) -rich layers, leading to a slight C contamination in their surfaces at â ¼10â 000 K. In this paper we aim to study the Gaia bifurcation as the natural consequence of C dredge-up by convection in cold He-dominated white dwarfs. Methods. Relying on accurate atmosphere models, we provide a new set of evolutionary models for He-rich white dwarfs, which employ different prescriptions for the C enrichment. On the basis of these models, we carried out a population synthesis study of the Gaia 100 pc white dwarf sample to constrain the models that best fit the bifurcation. Results. Our study shows that He-rich white dwarf models with a slight C contamination below the optical detection limit can accurately reproduce the Gaia bifurcation. We refer to these stars as â stealth DQâ white dwarfs because they do not exhibit detectable C signatures in their optical spectra, but the presence of C in their atmosphere produces a continuum absorption favoring the emission in bluer wavelengths, thereby creating the B branch of the bifurcation. Furthermore, our study shows that the white dwarf mass distribution obtained when a stealth C contamination is taken into account presents a peak at â ¼0.6â Mâ , which is consistent with the mass distribution for H-rich white dwarfs and with the standard evolutionary channels for their formation. Conclusions. We conclude that stealth DQ white dwarfs can account for the lower branch in the Gaia bifurcation. The C signatures of these stars could be detectable in ultraviolet (UV) spectra.
publishDate 2023
dc.date.none.fl_str_mv 2023-06
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
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://hdl.handle.net/11336/218790
Camisassa, Maria; Torres, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; et al.; A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation; EDP Sciences; Astronomy and Astrophysics; 674; A213; 6-2023; 1-9
0004-6361
CONICET Digital
CONICET
url http://hdl.handle.net/11336/218790
identifier_str_mv Camisassa, Maria; Torres, Santiago; Hollands, Mark; Koester, Detlev; Raddi, Roberto; et al.; A hidden population of white dwarfs with atmospheric carbon traces in the Gaia bifurcation; EDP Sciences; Astronomy and Astrophysics; 674; A213; 6-2023; 1-9
0004-6361
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/10.1051/0004-6361/202346628
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/202346628
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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