Asteroseismology of pulsating low-mass white dwarf stars
Autor(a) principal: | |
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Data de Publicação: | 2024 |
Tipo de documento: | Tese |
Idioma: | eng |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/274558 |
Resumo: | White dwarf stars are the most common final stage of stellar evolution, corresponding to 99% of all stars in the Galaxy. Around 10% of white dwarfs in the solar neighbourhood are low-mass (< 0.45M⊙) objects. In the case of low-mass white dwarfs, up to 70% of them are in binary systems. The total number of stars in such systems increases to 100% when extremely low-mass white dwarfs are considered. The pulsating low-mass white dwarf stars have stellar masses between 0.30 M⊙ and 0.45 M⊙ and show photometric variability due to gravity-mode pulsations. Within this mass range, they can harbour both a helium- and hybrid-core, depending if the progenitor experienced helium-core burning during the prewhite dwarf evolution. The eclipsing binary system SDSS J115219.99+024814.4 is composed of two low-mass white dwarfs with stellar masses of 0.362±0.014 M⊙ and 0.325±0.013 M⊙. The less massive component is a pulsating star, showing at least three pulsation periods of ∼1314 s, ∼1069 s, and ∼582.9 s. This opens the way to use asteroseismology as a tool to uncover its inner chemical structure, in combination with the information obtained using the light-curve modeling of the eclipses. By means of binary evolutionary models leading to helium- and hybrid-core white dwarfs, we computed adiabatic pulsations for ℓ = 1 and ℓ = 2 gravity modes with GYRE. We found that the pulsating component of the SDSS J115219.99+024814.4 system must have a hydrogen envelope thinner than the value obtained from binary evolution computations, independently of the inner composition. Finally, from our asteroseismological study, we find a best fit model characterised by Teff = 10 917 K, M=0.338 M⊙, MH = 10−6 M⊙ with the inner composition of a hybrid white dwarf. |
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Ramos, Gabriel LaufferRomero, Alejandra Daniela2024-04-11T06:25:14Z2024http://hdl.handle.net/10183/274558001200318White dwarf stars are the most common final stage of stellar evolution, corresponding to 99% of all stars in the Galaxy. Around 10% of white dwarfs in the solar neighbourhood are low-mass (< 0.45M⊙) objects. In the case of low-mass white dwarfs, up to 70% of them are in binary systems. The total number of stars in such systems increases to 100% when extremely low-mass white dwarfs are considered. The pulsating low-mass white dwarf stars have stellar masses between 0.30 M⊙ and 0.45 M⊙ and show photometric variability due to gravity-mode pulsations. Within this mass range, they can harbour both a helium- and hybrid-core, depending if the progenitor experienced helium-core burning during the prewhite dwarf evolution. The eclipsing binary system SDSS J115219.99+024814.4 is composed of two low-mass white dwarfs with stellar masses of 0.362±0.014 M⊙ and 0.325±0.013 M⊙. The less massive component is a pulsating star, showing at least three pulsation periods of ∼1314 s, ∼1069 s, and ∼582.9 s. This opens the way to use asteroseismology as a tool to uncover its inner chemical structure, in combination with the information obtained using the light-curve modeling of the eclipses. By means of binary evolutionary models leading to helium- and hybrid-core white dwarfs, we computed adiabatic pulsations for ℓ = 1 and ℓ = 2 gravity modes with GYRE. We found that the pulsating component of the SDSS J115219.99+024814.4 system must have a hydrogen envelope thinner than the value obtained from binary evolution computations, independently of the inner composition. Finally, from our asteroseismological study, we find a best fit model characterised by Teff = 10 917 K, M=0.338 M⊙, MH = 10−6 M⊙ with the inner composition of a hybrid white dwarf.application/pdfengAsterosismologiaAnãs brancasSistema binárioAsteroseismologyWhite dwarfBinary systemAsteroseismology of pulsating low-mass white dwarf starsAstrossismologia de estrelas anãs brancas pulsantes de baixa massa info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/doctoralThesisUniversidade Federal do Rio Grande do SulInstituto de FísicaPrograma de Pós-Graduação em FísicaPorto Alegre, BR-RS2024doutoradoinfo:eu-repo/semantics/openAccessreponame:Biblioteca Digital de Teses e Dissertações da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001200318.pdf.txt001200318.pdf.txtExtracted Texttext/plain250263http://www.lume.ufrgs.br/bitstream/10183/274558/2/001200318.pdf.txta2a6075f7ba45f7af1ad030ef5545a74MD52ORIGINAL001200318.pdfTexto completoapplication/pdf4783222http://www.lume.ufrgs.br/bitstream/10183/274558/1/001200318.pdf57f4a3e6c1eabb146567ba4bd6ad3ac2MD5110183/2745582024-08-29 06:33:44.361009oai:www.lume.ufrgs.br:10183/274558Biblioteca Digital de Teses e Dissertaçõeshttps://lume.ufrgs.br/handle/10183/2PUBhttps://lume.ufrgs.br/oai/requestlume@ufrgs.br||lume@ufrgs.bropendoar:18532024-08-29T09:33:44Biblioteca Digital de Teses e Dissertações da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Asteroseismology of pulsating low-mass white dwarf stars |
dc.title.alternative.pt.fl_str_mv |
Astrossismologia de estrelas anãs brancas pulsantes de baixa massa |
title |
Asteroseismology of pulsating low-mass white dwarf stars |
spellingShingle |
Asteroseismology of pulsating low-mass white dwarf stars Ramos, Gabriel Lauffer Asterosismologia Anãs brancas Sistema binário Asteroseismology White dwarf Binary system |
title_short |
Asteroseismology of pulsating low-mass white dwarf stars |
title_full |
Asteroseismology of pulsating low-mass white dwarf stars |
title_fullStr |
Asteroseismology of pulsating low-mass white dwarf stars |
title_full_unstemmed |
Asteroseismology of pulsating low-mass white dwarf stars |
title_sort |
Asteroseismology of pulsating low-mass white dwarf stars |
author |
Ramos, Gabriel Lauffer |
author_facet |
Ramos, Gabriel Lauffer |
author_role |
author |
dc.contributor.author.fl_str_mv |
Ramos, Gabriel Lauffer |
dc.contributor.advisor1.fl_str_mv |
Romero, Alejandra Daniela |
contributor_str_mv |
Romero, Alejandra Daniela |
dc.subject.por.fl_str_mv |
Asterosismologia Anãs brancas Sistema binário |
topic |
Asterosismologia Anãs brancas Sistema binário Asteroseismology White dwarf Binary system |
dc.subject.eng.fl_str_mv |
Asteroseismology White dwarf Binary system |
description |
White dwarf stars are the most common final stage of stellar evolution, corresponding to 99% of all stars in the Galaxy. Around 10% of white dwarfs in the solar neighbourhood are low-mass (< 0.45M⊙) objects. In the case of low-mass white dwarfs, up to 70% of them are in binary systems. The total number of stars in such systems increases to 100% when extremely low-mass white dwarfs are considered. The pulsating low-mass white dwarf stars have stellar masses between 0.30 M⊙ and 0.45 M⊙ and show photometric variability due to gravity-mode pulsations. Within this mass range, they can harbour both a helium- and hybrid-core, depending if the progenitor experienced helium-core burning during the prewhite dwarf evolution. The eclipsing binary system SDSS J115219.99+024814.4 is composed of two low-mass white dwarfs with stellar masses of 0.362±0.014 M⊙ and 0.325±0.013 M⊙. The less massive component is a pulsating star, showing at least three pulsation periods of ∼1314 s, ∼1069 s, and ∼582.9 s. This opens the way to use asteroseismology as a tool to uncover its inner chemical structure, in combination with the information obtained using the light-curve modeling of the eclipses. By means of binary evolutionary models leading to helium- and hybrid-core white dwarfs, we computed adiabatic pulsations for ℓ = 1 and ℓ = 2 gravity modes with GYRE. We found that the pulsating component of the SDSS J115219.99+024814.4 system must have a hydrogen envelope thinner than the value obtained from binary evolution computations, independently of the inner composition. Finally, from our asteroseismological study, we find a best fit model characterised by Teff = 10 917 K, M=0.338 M⊙, MH = 10−6 M⊙ with the inner composition of a hybrid white dwarf. |
publishDate |
2024 |
dc.date.accessioned.fl_str_mv |
2024-04-11T06:25:14Z |
dc.date.issued.fl_str_mv |
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info:eu-repo/semantics/doctoralThesis |
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