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
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/218790
Ver los metadatos del registro completo
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oai:ri.conicet.gov.ar:11336/218790 |
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3498 |
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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 |
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reponame:CONICET Digital (CONICET) instname:Consejo Nacional de Investigaciones Científicas y Técnicas |
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CONICET Digital (CONICET) |
collection |
CONICET Digital (CONICET) |
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Consejo Nacional de Investigaciones Científicas y Técnicas |
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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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1844613468191195136 |
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13.070432 |