ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres

Autores
Battich, Tiara; Miller Bertolami, Marcelo Miguel; Córsico, Alejandro Hugo; Althaus, Leandro Gabriel
Año de publicación
2017
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The ε mechanism is a self-excitation mechanism of stellar pulsations which acts in regions where nuclear burning takes place. It has been shown that the ε mechanism can excite pulsations in hot pre-horizontal branch stars before they settle into the stable helium core-burning phase and that the shortest periods of LS IV-14º116 could be explained that way.We aim to study the ε mechanism in stellar models appropriate for hot pre-horizontal branch stars to predict their pulsational properties.We perform detailed computations of non-adiabatic non-radial pulsations on such stellar models.We predict a new instability domain of long-period gravity modes in the log g−log T eff plane at roughly 22000 K ≲ Te ≲ 50000 K and 4.67 ≲ log g ≲ 6.15, with a period range from ∼ 200 to ∼ 2000 s. Comparison with the three known pulsating He-rich subdwarfs shows that the ε mechanism can excite pulsations in models with similar surface properties except for modes with the shortest observed periods. Based on simple estimates we expect at least 3 stars in the current samples of hot-subdwarf stars to be pulsating by the ε mechanism. Our results could constitute a theoretical basis for future searches of pulsators in the Galactic field.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-nd/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/81693

id SEDICI_15eab37376c946b27ba74c98ca43383a
oai_identifier_str oai:sedici.unlp.edu.ar:10915/81693
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheresBattich, TiaraMiller Bertolami, Marcelo MiguelCórsico, Alejandro HugoAlthaus, Leandro GabrielCiencias Astronómicaslow-mass starsstellar oscillationshorizontal-branch starsThe ε mechanism is a self-excitation mechanism of stellar pulsations which acts in regions where nuclear burning takes place. It has been shown that the ε mechanism can excite pulsations in hot pre-horizontal branch stars before they settle into the stable helium core-burning phase and that the shortest periods of LS IV-14º116 could be explained that way.We aim to study the ε mechanism in stellar models appropriate for hot pre-horizontal branch stars to predict their pulsational properties.We perform detailed computations of non-adiabatic non-radial pulsations on such stellar models.We predict a new instability domain of long-period gravity modes in the log g−log T eff plane at roughly 22000 K ≲ Te ≲ 50000 K and 4.67 ≲ log g ≲ 6.15, with a period range from ∼ 200 to ∼ 2000 s. Comparison with the three known pulsating He-rich subdwarfs shows that the ε mechanism can excite pulsations in models with similar surface properties except for modes with the shortest observed periods. Based on simple estimates we expect at least 3 stars in the current samples of hot-subdwarf stars to be pulsating by the ε mechanism. Our results could constitute a theoretical basis for future searches of pulsators in the Galactic field.Facultad de Ciencias Astronómicas y Geofísicas2017info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf152-159http://sedici.unlp.edu.ar/handle/10915/81693enginfo:eu-repo/semantics/altIdentifier/issn/2543-6376info:eu-repo/semantics/altIdentifier/doi/10.1515/astro-2017-0431info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-nd/4.0/Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:12Zoai:sedici.unlp.edu.ar:10915/81693Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:12.695SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
title ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
spellingShingle ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
Battich, Tiara
Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
title_short ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
title_full ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
title_fullStr ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
title_full_unstemmed ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
title_sort ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
dc.creator.none.fl_str_mv Battich, Tiara
Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author Battich, Tiara
author_facet Battich, Tiara
Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author_role author
author2 Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
topic Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
dc.description.none.fl_txt_mv The ε mechanism is a self-excitation mechanism of stellar pulsations which acts in regions where nuclear burning takes place. It has been shown that the ε mechanism can excite pulsations in hot pre-horizontal branch stars before they settle into the stable helium core-burning phase and that the shortest periods of LS IV-14º116 could be explained that way.We aim to study the ε mechanism in stellar models appropriate for hot pre-horizontal branch stars to predict their pulsational properties.We perform detailed computations of non-adiabatic non-radial pulsations on such stellar models.We predict a new instability domain of long-period gravity modes in the log g−log T eff plane at roughly 22000 K ≲ Te ≲ 50000 K and 4.67 ≲ log g ≲ 6.15, with a period range from ∼ 200 to ∼ 2000 s. Comparison with the three known pulsating He-rich subdwarfs shows that the ε mechanism can excite pulsations in models with similar surface properties except for modes with the shortest observed periods. Based on simple estimates we expect at least 3 stars in the current samples of hot-subdwarf stars to be pulsating by the ε mechanism. Our results could constitute a theoretical basis for future searches of pulsators in the Galactic field.
Facultad de Ciencias Astronómicas y Geofísicas
description The ε mechanism is a self-excitation mechanism of stellar pulsations which acts in regions where nuclear burning takes place. It has been shown that the ε mechanism can excite pulsations in hot pre-horizontal branch stars before they settle into the stable helium core-burning phase and that the shortest periods of LS IV-14º116 could be explained that way.We aim to study the ε mechanism in stellar models appropriate for hot pre-horizontal branch stars to predict their pulsational properties.We perform detailed computations of non-adiabatic non-radial pulsations on such stellar models.We predict a new instability domain of long-period gravity modes in the log g−log T eff plane at roughly 22000 K ≲ Te ≲ 50000 K and 4.67 ≲ log g ≲ 6.15, with a period range from ∼ 200 to ∼ 2000 s. Comparison with the three known pulsating He-rich subdwarfs shows that the ε mechanism can excite pulsations in models with similar surface properties except for modes with the shortest observed periods. Based on simple estimates we expect at least 3 stars in the current samples of hot-subdwarf stars to be pulsating by the ε mechanism. Our results could constitute a theoretical basis for future searches of pulsators in the Galactic field.
publishDate 2017
dc.date.none.fl_str_mv 2017
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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://sedici.unlp.edu.ar/handle/10915/81693
url http://sedici.unlp.edu.ar/handle/10915/81693
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/2543-6376
info:eu-repo/semantics/altIdentifier/doi/10.1515/astro-2017-0431
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-nd/4.0/
Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
dc.format.none.fl_str_mv application/pdf
152-159
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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