Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties
- Autores
- Althaus, Leandro Gabriel; Córsico, Alejandro Hugo; Miller Bertolami, Marcelo Miguel
- Año de publicación
- 2007
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- Aims, We examine a recently-proposed evolutionary scenario that could explain the existence of the low-mass, helium-enriched PG 1159 stars. We focus in particular on studying the pulsational stability properties of the evolutionary models predicted by such a scenario. Methods. We assess the overstability of pulsation g-modes of stellar models as evolution proceeds in the PG 1159 domain. Stellar models are extracted from the full evolution of a 1-M⊙ model star that experiences its first thermal pulse as a late thermal pulse (LTP) after leaving the AGB. The evolutionary stages corresponding to the born-again episode and the subsequent helium sub-flashes are taken into account in detail. Results. Under reasonable assumptions of mass-loss rate, the evolutionary scenario reproduces the high helium abundances observed in some PG 1159 stars. We find that, despite the high helium abundance in the driving layers, a narrow region exists in the log Teff - log g diagram for which the helium-enriched PG 1159 sequence exhibits unstable pulsation modes with periods in the range 500 to 1600 s. In particular, the nonpulsating helium-enriched PG 1159 star, MCT 0130-1937, is located outside the theoretical instability domain. Our results suggest that MCT 0130-1937 is a real non-pulsating star and that the lack of pulsations should not be attributed to unfavorable geometry. Conclusions. Our study hints at a consistent picture between the evolutionary scenario that could explain the existence of heliumenriched PG 1159 stars and the nonvariable nature of MCT 0130-1937. We also present theoretical support for the unusually high helium abundance observed in the nonpulsating PG 1159 star HS 1517+7403. We suggest that HS 1517+7403 could be a transition object linking the low-mass helium-rich O(He) stars with the helium-enriched PG 1159 stars via the evolutionary connection K1-27 →HS 1517+7403 → MCT 0130-1937.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto de Astrofísica de La Plata - Materia
-
Ciencias Astronómicas
Stars: abundances
Stars: AGB and post-AGB
Stars: evolution
Stars: interiors
Stars: variables: general
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:10915/83336
Ver los metadatos del registro completo
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Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability propertiesAlthaus, Leandro GabrielCórsico, Alejandro HugoMiller Bertolami, Marcelo MiguelCiencias AstronómicasStars: abundancesStars: AGB and post-AGBStars: evolutionStars: interiorsStars: variables: generalWhite dwarfsAims, We examine a recently-proposed evolutionary scenario that could explain the existence of the low-mass, helium-enriched PG 1159 stars. We focus in particular on studying the pulsational stability properties of the evolutionary models predicted by such a scenario. Methods. We assess the overstability of pulsation g-modes of stellar models as evolution proceeds in the PG 1159 domain. Stellar models are extracted from the full evolution of a 1-M⊙ model star that experiences its first thermal pulse as a late thermal pulse (LTP) after leaving the AGB. The evolutionary stages corresponding to the born-again episode and the subsequent helium sub-flashes are taken into account in detail. Results. Under reasonable assumptions of mass-loss rate, the evolutionary scenario reproduces the high helium abundances observed in some PG 1159 stars. We find that, despite the high helium abundance in the driving layers, a narrow region exists in the log T<SUB>eff</SUB> - log g diagram for which the helium-enriched PG 1159 sequence exhibits unstable pulsation modes with periods in the range 500 to 1600 s. In particular, the nonpulsating helium-enriched PG 1159 star, MCT 0130-1937, is located outside the theoretical instability domain. Our results suggest that MCT 0130-1937 is a real non-pulsating star and that the lack of pulsations should not be attributed to unfavorable geometry. Conclusions. Our study hints at a consistent picture between the evolutionary scenario that could explain the existence of heliumenriched PG 1159 stars and the nonvariable nature of MCT 0130-1937. We also present theoretical support for the unusually high helium abundance observed in the nonpulsating PG 1159 star HS 1517+7403. We suggest that HS 1517+7403 could be a transition object linking the low-mass helium-rich O(He) stars with the helium-enriched PG 1159 stars via the evolutionary connection K1-27 →HS 1517+7403 → MCT 0130-1937.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plata2007info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1175-1180http://sedici.unlp.edu.ar/handle/10915/83336enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20066887info: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:UNLP2025-09-29T11:15:41Zoai:sedici.unlp.edu.ar:10915/83336Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:42.16SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
title |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
spellingShingle |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties Althaus, Leandro Gabriel Ciencias Astronómicas Stars: abundances Stars: AGB and post-AGB Stars: evolution Stars: interiors Stars: variables: general White dwarfs |
title_short |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
title_full |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
title_fullStr |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
title_full_unstemmed |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
title_sort |
Low-mass, helium-enriched PG1159 stars: A possible evolutionary origin and implications for their pulsational stability properties |
dc.creator.none.fl_str_mv |
Althaus, Leandro Gabriel Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author |
Althaus, Leandro Gabriel |
author_facet |
Althaus, Leandro Gabriel Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author_role |
author |
author2 |
Córsico, Alejandro Hugo Miller Bertolami, Marcelo Miguel |
author2_role |
author author |
dc.subject.none.fl_str_mv |
Ciencias Astronómicas Stars: abundances Stars: AGB and post-AGB Stars: evolution Stars: interiors Stars: variables: general White dwarfs |
topic |
Ciencias Astronómicas Stars: abundances Stars: AGB and post-AGB Stars: evolution Stars: interiors Stars: variables: general White dwarfs |
dc.description.none.fl_txt_mv |
Aims, We examine a recently-proposed evolutionary scenario that could explain the existence of the low-mass, helium-enriched PG 1159 stars. We focus in particular on studying the pulsational stability properties of the evolutionary models predicted by such a scenario. Methods. We assess the overstability of pulsation g-modes of stellar models as evolution proceeds in the PG 1159 domain. Stellar models are extracted from the full evolution of a 1-M⊙ model star that experiences its first thermal pulse as a late thermal pulse (LTP) after leaving the AGB. The evolutionary stages corresponding to the born-again episode and the subsequent helium sub-flashes are taken into account in detail. Results. Under reasonable assumptions of mass-loss rate, the evolutionary scenario reproduces the high helium abundances observed in some PG 1159 stars. We find that, despite the high helium abundance in the driving layers, a narrow region exists in the log T<SUB>eff</SUB> - log g diagram for which the helium-enriched PG 1159 sequence exhibits unstable pulsation modes with periods in the range 500 to 1600 s. In particular, the nonpulsating helium-enriched PG 1159 star, MCT 0130-1937, is located outside the theoretical instability domain. Our results suggest that MCT 0130-1937 is a real non-pulsating star and that the lack of pulsations should not be attributed to unfavorable geometry. Conclusions. Our study hints at a consistent picture between the evolutionary scenario that could explain the existence of heliumenriched PG 1159 stars and the nonvariable nature of MCT 0130-1937. We also present theoretical support for the unusually high helium abundance observed in the nonpulsating PG 1159 star HS 1517+7403. We suggest that HS 1517+7403 could be a transition object linking the low-mass helium-rich O(He) stars with the helium-enriched PG 1159 stars via the evolutionary connection K1-27 →HS 1517+7403 → MCT 0130-1937. Facultad de Ciencias Astronómicas y Geofísicas Instituto de Astrofísica de La Plata |
description |
Aims, We examine a recently-proposed evolutionary scenario that could explain the existence of the low-mass, helium-enriched PG 1159 stars. We focus in particular on studying the pulsational stability properties of the evolutionary models predicted by such a scenario. Methods. We assess the overstability of pulsation g-modes of stellar models as evolution proceeds in the PG 1159 domain. Stellar models are extracted from the full evolution of a 1-M⊙ model star that experiences its first thermal pulse as a late thermal pulse (LTP) after leaving the AGB. The evolutionary stages corresponding to the born-again episode and the subsequent helium sub-flashes are taken into account in detail. Results. Under reasonable assumptions of mass-loss rate, the evolutionary scenario reproduces the high helium abundances observed in some PG 1159 stars. We find that, despite the high helium abundance in the driving layers, a narrow region exists in the log T<SUB>eff</SUB> - log g diagram for which the helium-enriched PG 1159 sequence exhibits unstable pulsation modes with periods in the range 500 to 1600 s. In particular, the nonpulsating helium-enriched PG 1159 star, MCT 0130-1937, is located outside the theoretical instability domain. Our results suggest that MCT 0130-1937 is a real non-pulsating star and that the lack of pulsations should not be attributed to unfavorable geometry. Conclusions. Our study hints at a consistent picture between the evolutionary scenario that could explain the existence of heliumenriched PG 1159 stars and the nonvariable nature of MCT 0130-1937. We also present theoretical support for the unusually high helium abundance observed in the nonpulsating PG 1159 star HS 1517+7403. We suggest that HS 1517+7403 could be a transition object linking the low-mass helium-rich O(He) stars with the helium-enriched PG 1159 stars via the evolutionary connection K1-27 →HS 1517+7403 → MCT 0130-1937. |
publishDate |
2007 |
dc.date.none.fl_str_mv |
2007 |
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 |
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article |
status_str |
publishedVersion |
dc.identifier.none.fl_str_mv |
http://sedici.unlp.edu.ar/handle/10915/83336 |
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http://sedici.unlp.edu.ar/handle/10915/83336 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/issn/0004-6361 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20066887 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) |
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openAccess |
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http://creativecommons.org/licenses/by-nc-sa/4.0/ Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0) |
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