Asteroseismic signatures of the helium-core flash

All evolved stars with masses M⋆ ≲ 2M ⊙ undergo a helium(He)-core flash at the end of their first stage as a giant star. Although theoretically predicted more than 50 years ago, this core-flash phase has yet to be observationally probed. We show here that gravity modes (g modes) stochastically excit...

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Detalles Bibliográficos
Autores principales: Miller Bertolami, Marcelo Miguel, Battich, Tiara, Córsico, Alejandro Hugo, Christensen-Dalsgaard, Jørgen, Althaus, Leandro Gabriel
Formato: Articulo Preprint
Lenguaje:Inglés
Publicado: 2019
Materias:
Ciencias Astronómicas
Subdwarf
Physics
Stars
Exoplanet
Amplitude
Excited state
Astrophysics
Helium
Photometry (optics)
Giant star
Solar mass
Flash (photography)
Acceso en línea:http://sedici.unlp.edu.ar/handle/10915/126824
Aporte de:
SEDICI (UNLP) de Universidad Nacional de La Plata
id I19-R120-10915-126824
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
Subdwarf
Physics
Stars
Exoplanet
Amplitude
Excited state
Astrophysics
Helium
Photometry (optics)
Giant star
Solar mass
Flash (photography)
spellingShingle Ciencias Astronómicas
Subdwarf
Physics
Stars
Exoplanet
Amplitude
Excited state
Astrophysics
Helium
Photometry (optics)
Giant star
Solar mass
Flash (photography)
Miller Bertolami, Marcelo Miguel
Battich, Tiara
Córsico, Alejandro Hugo
Christensen-Dalsgaard, Jørgen
Althaus, Leandro Gabriel
Asteroseismic signatures of the helium-core flash
topic_facet Ciencias Astronómicas
Subdwarf
Physics
Stars
Exoplanet
Amplitude
Excited state
Astrophysics
Helium
Photometry (optics)
Giant star
Solar mass
Flash (photography)
description All evolved stars with masses M⋆ ≲ 2M ⊙ undergo a helium(He)-core flash at the end of their first stage as a giant star. Although theoretically predicted more than 50 years ago, this core-flash phase has yet to be observationally probed. We show here that gravity modes (g modes) stochastically excited by He-flash driven convection are able to reach the stellar surface, and induce periodic photometric variabilities in hot-subdwarf stars with amplitudes of the order of a few mmag. As such they can now be detected by spacebased photometry with the Transiting Exoplanet Survey Satellite (TESS) in relatively bright stars (e.g. magnitudes IC ≲13). The range of predicted periods spans from a few thousand seconds to tens of thousand seconds, depending on the details of the excitation region. In addition, we find that stochastically excited pulsations reproduce the pulsations observed in a couple of He-rich hot subdwarf stars. These stars, and in particular the future TESS target Feige 46, are the most promising candidates to probe the He-core flash for the first time.
format Articulo
Preprint
author Miller Bertolami, Marcelo Miguel
Battich, Tiara
Córsico, Alejandro Hugo
Christensen-Dalsgaard, Jørgen
Althaus, Leandro Gabriel
author_facet Miller Bertolami, Marcelo Miguel
Battich, Tiara
Córsico, Alejandro Hugo
Christensen-Dalsgaard, Jørgen
Althaus, Leandro Gabriel
author_sort Miller Bertolami, Marcelo Miguel
title Asteroseismic signatures of the helium-core flash
title_short Asteroseismic signatures of the helium-core flash
title_full Asteroseismic signatures of the helium-core flash
title_fullStr Asteroseismic signatures of the helium-core flash
title_full_unstemmed Asteroseismic signatures of the helium-core flash
title_sort asteroseismic signatures of the helium-core flash
publishDate 2019
url http://sedici.unlp.edu.ar/handle/10915/126824
work_keys_str_mv AT millerbertolamimarcelomiguel asteroseismicsignaturesoftheheliumcoreflash
AT battichtiara asteroseismicsignaturesoftheheliumcoreflash
AT corsicoalejandrohugo asteroseismicsignaturesoftheheliumcoreflash
AT christensendalsgaardjørgen asteroseismicsignaturesoftheheliumcoreflash
AT althausleandrogabriel asteroseismicsignaturesoftheheliumcoreflash
bdutipo_str Repositorios
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