Asteroseismology of pulsating low-mass white dwarf stars

Detalhes bibliográficos
Autor(a) principal: Ramos, Gabriel Lauffer
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.
id URGS_0845a5cbd3ff336bacb37f397e49346d
oai_identifier_str oai:www.lume.ufrgs.br:10183/274558
network_acronym_str URGS
network_name_str Biblioteca Digital de Teses e Dissertações da UFRGS
repository_id_str 1853
spelling 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 2024
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/doctoralThesis
format doctoralThesis
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10183/274558
dc.identifier.nrb.pt_BR.fl_str_mv 001200318
url http://hdl.handle.net/10183/274558
identifier_str_mv 001200318
dc.language.iso.fl_str_mv eng
language eng
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv reponame:Biblioteca Digital de Teses e Dissertações da UFRGS
instname:Universidade Federal do Rio Grande do Sul (UFRGS)
instacron:UFRGS
instname_str Universidade Federal do Rio Grande do Sul (UFRGS)
instacron_str UFRGS
institution UFRGS
reponame_str Biblioteca Digital de Teses e Dissertações da UFRGS
collection Biblioteca Digital de Teses e Dissertações da UFRGS
bitstream.url.fl_str_mv http://www.lume.ufrgs.br/bitstream/10183/274558/2/001200318.pdf.txt
http://www.lume.ufrgs.br/bitstream/10183/274558/1/001200318.pdf
bitstream.checksum.fl_str_mv a2a6075f7ba45f7af1ad030ef5545a74
57f4a3e6c1eabb146567ba4bd6ad3ac2
bitstream.checksumAlgorithm.fl_str_mv MD5
MD5
repository.name.fl_str_mv Biblioteca Digital de Teses e Dissertações da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)
repository.mail.fl_str_mv lume@ufrgs.br||lume@ufrgs.br
_version_ 1810085642192814080