Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff

Autores
Zorec, Juan; Cidale, Lydia Sonia; Arias, María Laura; Frémat, Y.; Muratore, M. F.; Torres, A. F.; Martayan, C.
Año de publicación
2009
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Context. Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. Aims. We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. Methods. The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. Results. We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. Conclusions. The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Stars: Early-type
Stars: fundamental parameters
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/82737

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/82737
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into TeffZorec, JuanCidale, Lydia SoniaArias, María LauraFrémat, Y.Muratore, M. F.Torres, A. F.Martayan, C.Ciencias AstronómicasStars: Early-typeStars: fundamental parameters<b>Context.</b> Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. <b>Aims.</b> We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. <b>Methods.</b> The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. <b>Results.</b> We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. <b>Conclusions.</b> The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.Facultad de Ciencias Astronómicas y Geofísicas2009-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf297-320http://sedici.unlp.edu.ar/handle/10915/82737enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/200811147info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by/4.0/Creative Commons Attribution 4.0 International (CC BY 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:35Zoai:sedici.unlp.edu.ar:10915/82737Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:36.311SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
title Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
spellingShingle Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
Zorec, Juan
Ciencias Astronómicas
Stars: Early-type
Stars: fundamental parameters
title_short Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
title_full Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
title_fullStr Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
title_full_unstemmed Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
title_sort Fundamental parameters of B supergiants from the BCD system: I. Calibration of the (λ1, D) parameters into Teff
dc.creator.none.fl_str_mv Zorec, Juan
Cidale, Lydia Sonia
Arias, María Laura
Frémat, Y.
Muratore, M. F.
Torres, A. F.
Martayan, C.
author Zorec, Juan
author_facet Zorec, Juan
Cidale, Lydia Sonia
Arias, María Laura
Frémat, Y.
Muratore, M. F.
Torres, A. F.
Martayan, C.
author_role author
author2 Cidale, Lydia Sonia
Arias, María Laura
Frémat, Y.
Muratore, M. F.
Torres, A. F.
Martayan, C.
author2_role author
author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Stars: Early-type
Stars: fundamental parameters
topic Ciencias Astronómicas
Stars: Early-type
Stars: fundamental parameters
dc.description.none.fl_txt_mv <b>Context.</b> Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. <b>Aims.</b> We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. <b>Methods.</b> The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. <b>Results.</b> We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. <b>Conclusions.</b> The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.
Facultad de Ciencias Astronómicas y Geofísicas
description <b>Context.</b> Effective temperatures of early-type supergiants are important to test stellar atmosphere- and internal structure-models of massive and intermediate mass objects at different evolutionary phases. However, these Teff values are more or less discrepant depending on the method used to determine them. <b>Aims.</b> We aim to obtain a new calibration of the T eff parameter for early-type supergiants as a function of observational quantities that are: a) highly sensitive to the ionization balance in the photosphere and its gas pressure; b) independent of the interstellar extinction; c) as much as possible model-independent. <b>Methods.</b> The observational quantities that best address our aims are the (λ1, D) parameters of the BCD spectrophotometric system. They describe the energy distribution around the Balmer discontinuity, which is highly sensitive to Teff and log g. We perform a calibration of the (λ 1, D) parameters into Teff using effective temperatures derived with the bolometric-flux method for 217 program stars, whose individual uncertainties are on average |ΔTeff|/Teff f = 0.05. <b>Results.</b> We obtain a new and homogeneous calibration of the BCD (λ1, D) parameters for OB supergiants and revisit the current calibration of the (λ1, D) zone occupied by dwarfs and giants. The final comparison of calculated with obtained Teff values in the (λ1, D) calibration show that the latter have total uncertainties, which on average are εTeff/Teff f ≃ ±0.05 for all spectral types and luminosity classes. <b>Conclusions.</b> The effective temperatures of OB supergiants derived in this work agree on average within some 2000 K with other determinations found in the literature, except those issued from wind-free non-LTE plane-parallel models of stellar atmospheres, which produce effective temperatures that can be overestimated by up to more than 5000 K near Teff = K. Since the stellar spectra needed to obtain the (λ1, D) parameters are of low resolution, a calibration based on the BCD system is useful to study stars and stellar systems like open clusters, associations or stars in galaxies observed with multi-object spectrographs and/or spectro-imaging devices.
publishDate 2009
dc.date.none.fl_str_mv 2009-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://sedici.unlp.edu.ar/handle/10915/82737
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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/10.1051/0004-6361/200811147
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by/4.0/
Creative Commons Attribution 4.0 International (CC BY 4.0)
dc.format.none.fl_str_mv application/pdf
297-320
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
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