New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution
- Autores
- Althaus, Leandro Gabriel; García-Berro, E.; Isern, J.; Córsico, Alejandro Hugo; Miller Bertolami, Marcelo Miguel
- Año de publicación
- 2012
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- Context. Cool white dwarfs are reliable and independent stellar chronometers. The most common white dwarfs have carbon-oxygen dense cores. Consequently, the cooling ages of very cool white dwarfs sensitively depend on the adopted phase diagram of the carbon-oxygen binary mixture. Aims. A new phase diagram of dense carbon-oxygen mixtures appropriate for white dwarf interiors has been recently obtained using direct molecular dynamics simulations. In this paper, we explore the consequences of this phase diagram in the evolution of cool white dwarfs. Methods. To do this we employ a detailed stellar evolutionary code and accurate initial white dwarf configurations, derived from the full evolution of progenitor stars. We use two different phase diagrams, that of Horowitz et al. (2010, Phys. Rev. Lett., 104, 231101), which presents an azeotrope, and the phase diagram of Segretain & Chabrier (1993, A&A, 271, L13), which is of the spindle form. Results. We computed the evolution of 0.593 and 0.878 M ⊙ white dwarf models during the crystallization phase, and we found that the energy released by carbon-oxygen phase separation is smaller when the new phase diagram of Horowitz et al. is used. This translates into time delays that are on average a factor ∼2 smaller than those obtained when the phase diagram of Segretain & Chabrier is employed. Conclusions. Our results have important implications for white dwarf cosmochronology, because the cooling ages of very old white dwarfs are different for the two phase diagrams. This may have a noticeable impact on the age determinations of very old globular clusters, for which the white dwarf color-magnitude diagram provides an independent way of estimating their age.
Facultad de Ciencias Astronómicas y Geofísicas - Materia
-
Ciencias Astronómicas
stars: evolution
stars: interiors
white dwarfs - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by-nc-sa/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/84416
Ver los metadatos del registro completo
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New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolutionAlthaus, Leandro GabrielGarcía-Berro, E.Isern, J.Córsico, Alejandro HugoMiller Bertolami, Marcelo MiguelCiencias Astronómicasstars: evolutionstars: interiorswhite dwarfsContext. Cool white dwarfs are reliable and independent stellar chronometers. The most common white dwarfs have carbon-oxygen dense cores. Consequently, the cooling ages of very cool white dwarfs sensitively depend on the adopted phase diagram of the carbon-oxygen binary mixture. Aims. A new phase diagram of dense carbon-oxygen mixtures appropriate for white dwarf interiors has been recently obtained using direct molecular dynamics simulations. In this paper, we explore the consequences of this phase diagram in the evolution of cool white dwarfs. Methods. To do this we employ a detailed stellar evolutionary code and accurate initial white dwarf configurations, derived from the full evolution of progenitor stars. We use two different phase diagrams, that of Horowitz et al. (2010, Phys. Rev. Lett., 104, 231101), which presents an azeotrope, and the phase diagram of Segretain & Chabrier (1993, A&A, 271, L13), which is of the spindle form. Results. We computed the evolution of 0.593 and 0.878 M ⊙ white dwarf models during the crystallization phase, and we found that the energy released by carbon-oxygen phase separation is smaller when the new phase diagram of Horowitz et al. is used. This translates into time delays that are on average a factor ∼2 smaller than those obtained when the phase diagram of Segretain & Chabrier is employed. Conclusions. Our results have important implications for white dwarf cosmochronology, because the cooling ages of very old white dwarfs are different for the two phase diagrams. This may have a noticeable impact on the age determinations of very old globular clusters, for which the white dwarf color-magnitude diagram provides an independent way of estimating their age.Facultad de Ciencias Astronómicas y Geofísicas2012info: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/10915/84416enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201117902info: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:UNLP2025-09-29T11:16:05Zoai:sedici.unlp.edu.ar:10915/84416Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:16:05.537SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
title |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
spellingShingle |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution Althaus, Leandro Gabriel Ciencias Astronómicas stars: evolution stars: interiors white dwarfs |
title_short |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
title_full |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
title_fullStr |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
title_full_unstemmed |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
title_sort |
New phase diagrams for dense carbon-oxygen mixtures and white dwarf evolution |
dc.creator.none.fl_str_mv |
Althaus, Leandro Gabriel García-Berro, E. Isern, J. Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author |
Althaus, Leandro Gabriel |
author_facet |
Althaus, Leandro Gabriel García-Berro, E. Isern, J. Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author_role |
author |
author2 |
García-Berro, E. Isern, J. Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author2_role |
author author author author |
dc.subject.none.fl_str_mv |
Ciencias Astronómicas stars: evolution stars: interiors white dwarfs |
topic |
Ciencias Astronómicas stars: evolution stars: interiors white dwarfs |
dc.description.none.fl_txt_mv |
Context. Cool white dwarfs are reliable and independent stellar chronometers. The most common white dwarfs have carbon-oxygen dense cores. Consequently, the cooling ages of very cool white dwarfs sensitively depend on the adopted phase diagram of the carbon-oxygen binary mixture. Aims. A new phase diagram of dense carbon-oxygen mixtures appropriate for white dwarf interiors has been recently obtained using direct molecular dynamics simulations. In this paper, we explore the consequences of this phase diagram in the evolution of cool white dwarfs. Methods. To do this we employ a detailed stellar evolutionary code and accurate initial white dwarf configurations, derived from the full evolution of progenitor stars. We use two different phase diagrams, that of Horowitz et al. (2010, Phys. Rev. Lett., 104, 231101), which presents an azeotrope, and the phase diagram of Segretain & Chabrier (1993, A&A, 271, L13), which is of the spindle form. Results. We computed the evolution of 0.593 and 0.878 M ⊙ white dwarf models during the crystallization phase, and we found that the energy released by carbon-oxygen phase separation is smaller when the new phase diagram of Horowitz et al. is used. This translates into time delays that are on average a factor ∼2 smaller than those obtained when the phase diagram of Segretain & Chabrier is employed. Conclusions. Our results have important implications for white dwarf cosmochronology, because the cooling ages of very old white dwarfs are different for the two phase diagrams. This may have a noticeable impact on the age determinations of very old globular clusters, for which the white dwarf color-magnitude diagram provides an independent way of estimating their age. Facultad de Ciencias Astronómicas y Geofísicas |
description |
Context. Cool white dwarfs are reliable and independent stellar chronometers. The most common white dwarfs have carbon-oxygen dense cores. Consequently, the cooling ages of very cool white dwarfs sensitively depend on the adopted phase diagram of the carbon-oxygen binary mixture. Aims. A new phase diagram of dense carbon-oxygen mixtures appropriate for white dwarf interiors has been recently obtained using direct molecular dynamics simulations. In this paper, we explore the consequences of this phase diagram in the evolution of cool white dwarfs. Methods. To do this we employ a detailed stellar evolutionary code and accurate initial white dwarf configurations, derived from the full evolution of progenitor stars. We use two different phase diagrams, that of Horowitz et al. (2010, Phys. Rev. Lett., 104, 231101), which presents an azeotrope, and the phase diagram of Segretain & Chabrier (1993, A&A, 271, L13), which is of the spindle form. Results. We computed the evolution of 0.593 and 0.878 M ⊙ white dwarf models during the crystallization phase, and we found that the energy released by carbon-oxygen phase separation is smaller when the new phase diagram of Horowitz et al. is used. This translates into time delays that are on average a factor ∼2 smaller than those obtained when the phase diagram of Segretain & Chabrier is employed. Conclusions. Our results have important implications for white dwarf cosmochronology, because the cooling ages of very old white dwarfs are different for the two phase diagrams. This may have a noticeable impact on the age determinations of very old globular clusters, for which the white dwarf color-magnitude diagram provides an independent way of estimating their age. |
publishDate |
2012 |
dc.date.none.fl_str_mv |
2012 |
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info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Articulo http://purl.org/coar/resource_type/c_6501 info:ar-repo/semantics/articulo |
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http://sedici.unlp.edu.ar/handle/10915/84416 |
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dc.language.none.fl_str_mv |
eng |
language |
eng |
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info:eu-repo/semantics/altIdentifier/issn/0004-6361 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201117902 |
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