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

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 shor...

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Autores principales: Battich, Tiara, Miller Bertolami, Marcelo Miguel, Córsico, Alejandro Hugo, Althaus, Leandro Gabriel
Formato: Articulo
Lenguaje:Inglés
Publicado: 2017
Materias:
Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/81693
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-81693
record_format dspace
institution Universidad Nacional de La Plata
institution_str I-19
repository_str R-120
collection SEDICI (UNLP)
language Inglés
topic Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
spellingShingle Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
Battich, Tiara
Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
topic_facet Ciencias Astronómicas
low-mass stars
stellar oscillations
horizontal-branch stars
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.
format Articulo
Articulo
author Battich, Tiara
Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author_facet Battich, Tiara
Miller Bertolami, Marcelo Miguel
Córsico, Alejandro Hugo
Althaus, Leandro Gabriel
author_sort Battich, Tiara
title ε-mechanism driven pulsations in hot subdwarf stars with mixed H-He atmospheres
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
publishDate 2017
url http://sedici.unlp.edu.ar/handle/10915/81693
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AT millerbertolamimarcelomiguel emechanismdrivenpulsationsinhotsubdwarfstarswithmixedhheatmospheres
AT corsicoalejandrohugo emechanismdrivenpulsationsinhotsubdwarfstarswithmixedhheatmospheres
AT althausleandrogabriel emechanismdrivenpulsationsinhotsubdwarfstarswithmixedhheatmospheres
bdutipo_str Repositorios
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