A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752

Autores
Hubrig, Svetlena; Castelli, Fiorella; de Silva, G.; Gonzalez, Jorge Federico; Momany, Y.; Netopil, M.; Moehler, S.
Año de publicación
2009
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Aims. Large abundance anomalies have been previously detected in Horizontal Branch B-type stars. It has been suggested that at Teff > 11 000 K the stellar atmospheres become susceptible to diffusion effects and thus develop surface abundances similar to those that appear in the main-sequence, chemically peculiar group of A and B-type stars. We present the first high-resolution study of isotopic anomalies and chemical abundances in six Horizontal Branch B-type stars in globular clusters NGC 6397 and NGC 6752 and compare them to those observed in HgMn stars. Methods. We obtained high-resolution (up to R ∼ 115000) UVES spectra of a representative sample of six B-type stars (T183, T191, T193, B652, B2151, B2206) with sharp spectral lines (v sin i ≤ 10kms-1). The stars T183 and B2151 were observed on two consecutive nights to examine potential spectrum variability. A detailed spectrum analysis was done relying on Kurucz ATLAS9 and ATLAS 12 models. The spectra were analysed using the SYNTHE code to generate synthetic spectra. Results. It is the first time an abundance analysis is performed for all elements for which spectral lines were detected in UVES spectra of Horizontal Branch B-type stars. Our study of these stars revealed no signs of He isotopic anomalies, which would produce a 3He/4He ratio different from the solar one. The isotopic anomaly of Ca is detected in all six studied stars. The chemical abundance analysis reveals an overabundance over the solar values of P, Ti, Mn, Fe, and Y and an overabundance over the cluster metallicity of Mg, Ca, and Cr. This behaviour is very similar in all six stars of both clusters with a few exceptions: the Na abundance is larger by more than 1.4 dex than the cluster metallicity in B652, and by more than 0.8 dex greater than the cluster metallicity in B2206; the Co abundance is 1.0 dex over the solar abundance for T191, while Zr is overabundant over the solar abundance by 0.4 dex in B2206. No lines of Hg or other heavy elements were observed in the spectra. Weak emission lines of Ti II, similar to those frequently observed in HgMn stars have been discovered in one Horizontal Branch B-type star T191. Furthermore, we detected a radial velocity change of 0.9km s-1 from one night to the next for T183 and 0.4 km s-1 for B215l. Further high-resolution observations are needed to examine whether both stars are spectroscopic binaries.
Fil: Hubrig, Svetlena. Astrophysical Institute Potsdam; Alemania
Fil: Castelli, Fiorella. Osservatorio Astronomico di Trieste; Italia
Fil: de Silva, G.. European Southern Observatory; Alemania
Fil: Gonzalez, Jorge Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina
Fil: Momany, Y.. Astrophysical Institute Potsdam; Alemania
Fil: Netopil, M.. Institut für Astronomie der Universität Wien; Austria
Fil: Moehler, S.. European Southem Observatory; Alemania
Materia
GALAXY: GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6397, NGC 6752
STARS: ABUNDANCES
STARS: ATMOSPHERES STARS: FUNDAMENTAL PARAMETERS
STARS: BINARIES: SPECTROSCOPIC
STARS: POPULATION II
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/205194

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network_name_str CONICET Digital (CONICET)
spelling A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752Hubrig, SvetlenaCastelli, Fiorellade Silva, G.Gonzalez, Jorge FedericoMomany, Y.Netopil, M.Moehler, S.GALAXY: GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6397, NGC 6752STARS: ABUNDANCESSTARS: ATMOSPHERES STARS: FUNDAMENTAL PARAMETERSSTARS: BINARIES: SPECTROSCOPICSTARS: POPULATION IIhttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Aims. Large abundance anomalies have been previously detected in Horizontal Branch B-type stars. It has been suggested that at Teff > 11 000 K the stellar atmospheres become susceptible to diffusion effects and thus develop surface abundances similar to those that appear in the main-sequence, chemically peculiar group of A and B-type stars. We present the first high-resolution study of isotopic anomalies and chemical abundances in six Horizontal Branch B-type stars in globular clusters NGC 6397 and NGC 6752 and compare them to those observed in HgMn stars. Methods. We obtained high-resolution (up to R ∼ 115000) UVES spectra of a representative sample of six B-type stars (T183, T191, T193, B652, B2151, B2206) with sharp spectral lines (v sin i ≤ 10kms-1). The stars T183 and B2151 were observed on two consecutive nights to examine potential spectrum variability. A detailed spectrum analysis was done relying on Kurucz ATLAS9 and ATLAS 12 models. The spectra were analysed using the SYNTHE code to generate synthetic spectra. Results. It is the first time an abundance analysis is performed for all elements for which spectral lines were detected in UVES spectra of Horizontal Branch B-type stars. Our study of these stars revealed no signs of He isotopic anomalies, which would produce a 3He/4He ratio different from the solar one. The isotopic anomaly of Ca is detected in all six studied stars. The chemical abundance analysis reveals an overabundance over the solar values of P, Ti, Mn, Fe, and Y and an overabundance over the cluster metallicity of Mg, Ca, and Cr. This behaviour is very similar in all six stars of both clusters with a few exceptions: the Na abundance is larger by more than 1.4 dex than the cluster metallicity in B652, and by more than 0.8 dex greater than the cluster metallicity in B2206; the Co abundance is 1.0 dex over the solar abundance for T191, while Zr is overabundant over the solar abundance by 0.4 dex in B2206. No lines of Hg or other heavy elements were observed in the spectra. Weak emission lines of Ti II, similar to those frequently observed in HgMn stars have been discovered in one Horizontal Branch B-type star T191. Furthermore, we detected a radial velocity change of 0.9km s-1 from one night to the next for T183 and 0.4 km s-1 for B215l. Further high-resolution observations are needed to examine whether both stars are spectroscopic binaries.Fil: Hubrig, Svetlena. Astrophysical Institute Potsdam; AlemaniaFil: Castelli, Fiorella. Osservatorio Astronomico di Trieste; ItaliaFil: de Silva, G.. European Southern Observatory; AlemaniaFil: Gonzalez, Jorge Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Momany, Y.. Astrophysical Institute Potsdam; AlemaniaFil: Netopil, M.. Institut für Astronomie der Universität Wien; AustriaFil: Moehler, S.. European Southem Observatory; AlemaniaEDP Sciences2009-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/205194Hubrig, Svetlena; Castelli, Fiorella; de Silva, G.; Gonzalez, Jorge Federico; Momany, Y.; et al.; A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752; EDP Sciences; Astronomy and Astrophysics; 499; 3; 12-2009; 865-8780004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/200911721info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:07:14Zoai:ri.conicet.gov.ar:11336/205194instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:07:14.657CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
title A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
spellingShingle A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
Hubrig, Svetlena
GALAXY: GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6397, NGC 6752
STARS: ABUNDANCES
STARS: ATMOSPHERES STARS: FUNDAMENTAL PARAMETERS
STARS: BINARIES: SPECTROSCOPIC
STARS: POPULATION II
title_short A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
title_full A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
title_fullStr A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
title_full_unstemmed A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
title_sort A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752
dc.creator.none.fl_str_mv Hubrig, Svetlena
Castelli, Fiorella
de Silva, G.
Gonzalez, Jorge Federico
Momany, Y.
Netopil, M.
Moehler, S.
author Hubrig, Svetlena
author_facet Hubrig, Svetlena
Castelli, Fiorella
de Silva, G.
Gonzalez, Jorge Federico
Momany, Y.
Netopil, M.
Moehler, S.
author_role author
author2 Castelli, Fiorella
de Silva, G.
Gonzalez, Jorge Federico
Momany, Y.
Netopil, M.
Moehler, S.
author2_role author
author
author
author
author
author
dc.subject.none.fl_str_mv GALAXY: GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6397, NGC 6752
STARS: ABUNDANCES
STARS: ATMOSPHERES STARS: FUNDAMENTAL PARAMETERS
STARS: BINARIES: SPECTROSCOPIC
STARS: POPULATION II
topic GALAXY: GLOBULAR CLUSTERS: INDIVIDUAL: NGC 6397, NGC 6752
STARS: ABUNDANCES
STARS: ATMOSPHERES STARS: FUNDAMENTAL PARAMETERS
STARS: BINARIES: SPECTROSCOPIC
STARS: POPULATION II
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Aims. Large abundance anomalies have been previously detected in Horizontal Branch B-type stars. It has been suggested that at Teff > 11 000 K the stellar atmospheres become susceptible to diffusion effects and thus develop surface abundances similar to those that appear in the main-sequence, chemically peculiar group of A and B-type stars. We present the first high-resolution study of isotopic anomalies and chemical abundances in six Horizontal Branch B-type stars in globular clusters NGC 6397 and NGC 6752 and compare them to those observed in HgMn stars. Methods. We obtained high-resolution (up to R ∼ 115000) UVES spectra of a representative sample of six B-type stars (T183, T191, T193, B652, B2151, B2206) with sharp spectral lines (v sin i ≤ 10kms-1). The stars T183 and B2151 were observed on two consecutive nights to examine potential spectrum variability. A detailed spectrum analysis was done relying on Kurucz ATLAS9 and ATLAS 12 models. The spectra were analysed using the SYNTHE code to generate synthetic spectra. Results. It is the first time an abundance analysis is performed for all elements for which spectral lines were detected in UVES spectra of Horizontal Branch B-type stars. Our study of these stars revealed no signs of He isotopic anomalies, which would produce a 3He/4He ratio different from the solar one. The isotopic anomaly of Ca is detected in all six studied stars. The chemical abundance analysis reveals an overabundance over the solar values of P, Ti, Mn, Fe, and Y and an overabundance over the cluster metallicity of Mg, Ca, and Cr. This behaviour is very similar in all six stars of both clusters with a few exceptions: the Na abundance is larger by more than 1.4 dex than the cluster metallicity in B652, and by more than 0.8 dex greater than the cluster metallicity in B2206; the Co abundance is 1.0 dex over the solar abundance for T191, while Zr is overabundant over the solar abundance by 0.4 dex in B2206. No lines of Hg or other heavy elements were observed in the spectra. Weak emission lines of Ti II, similar to those frequently observed in HgMn stars have been discovered in one Horizontal Branch B-type star T191. Furthermore, we detected a radial velocity change of 0.9km s-1 from one night to the next for T183 and 0.4 km s-1 for B215l. Further high-resolution observations are needed to examine whether both stars are spectroscopic binaries.
Fil: Hubrig, Svetlena. Astrophysical Institute Potsdam; Alemania
Fil: Castelli, Fiorella. Osservatorio Astronomico di Trieste; Italia
Fil: de Silva, G.. European Southern Observatory; Alemania
Fil: Gonzalez, Jorge Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina
Fil: Momany, Y.. Astrophysical Institute Potsdam; Alemania
Fil: Netopil, M.. Institut für Astronomie der Universität Wien; Austria
Fil: Moehler, S.. European Southem Observatory; Alemania
description Aims. Large abundance anomalies have been previously detected in Horizontal Branch B-type stars. It has been suggested that at Teff > 11 000 K the stellar atmospheres become susceptible to diffusion effects and thus develop surface abundances similar to those that appear in the main-sequence, chemically peculiar group of A and B-type stars. We present the first high-resolution study of isotopic anomalies and chemical abundances in six Horizontal Branch B-type stars in globular clusters NGC 6397 and NGC 6752 and compare them to those observed in HgMn stars. Methods. We obtained high-resolution (up to R ∼ 115000) UVES spectra of a representative sample of six B-type stars (T183, T191, T193, B652, B2151, B2206) with sharp spectral lines (v sin i ≤ 10kms-1). The stars T183 and B2151 were observed on two consecutive nights to examine potential spectrum variability. A detailed spectrum analysis was done relying on Kurucz ATLAS9 and ATLAS 12 models. The spectra were analysed using the SYNTHE code to generate synthetic spectra. Results. It is the first time an abundance analysis is performed for all elements for which spectral lines were detected in UVES spectra of Horizontal Branch B-type stars. Our study of these stars revealed no signs of He isotopic anomalies, which would produce a 3He/4He ratio different from the solar one. The isotopic anomaly of Ca is detected in all six studied stars. The chemical abundance analysis reveals an overabundance over the solar values of P, Ti, Mn, Fe, and Y and an overabundance over the cluster metallicity of Mg, Ca, and Cr. This behaviour is very similar in all six stars of both clusters with a few exceptions: the Na abundance is larger by more than 1.4 dex than the cluster metallicity in B652, and by more than 0.8 dex greater than the cluster metallicity in B2206; the Co abundance is 1.0 dex over the solar abundance for T191, while Zr is overabundant over the solar abundance by 0.4 dex in B2206. No lines of Hg or other heavy elements were observed in the spectra. Weak emission lines of Ti II, similar to those frequently observed in HgMn stars have been discovered in one Horizontal Branch B-type star T191. Furthermore, we detected a radial velocity change of 0.9km s-1 from one night to the next for T183 and 0.4 km s-1 for B215l. Further high-resolution observations are needed to examine whether both stars are spectroscopic binaries.
publishDate 2009
dc.date.none.fl_str_mv 2009-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
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://hdl.handle.net/11336/205194
Hubrig, Svetlena; Castelli, Fiorella; de Silva, G.; Gonzalez, Jorge Federico; Momany, Y.; et al.; A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752; EDP Sciences; Astronomy and Astrophysics; 499; 3; 12-2009; 865-878
0004-6361
CONICET Digital
CONICET
url http://hdl.handle.net/11336/205194
identifier_str_mv Hubrig, Svetlena; Castelli, Fiorella; de Silva, G.; Gonzalez, Jorge Federico; Momany, Y.; et al.; A high-resolution study of isotopic composition and chemical abundances of blue horizontal branch stars in the globular clusters NGC 6397 and NGC 6752; EDP Sciences; Astronomy and Astrophysics; 499; 3; 12-2009; 865-878
0004-6361
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/200911721
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.format.none.fl_str_mv application/pdf
application/pdf
dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
dc.source.none.fl_str_mv reponame:CONICET Digital (CONICET)
instname:Consejo Nacional de Investigaciones Científicas y Técnicas
reponame_str CONICET Digital (CONICET)
collection CONICET Digital (CONICET)
instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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