New insights into the nature of the peculiar star θ Carinae

Autores
Hubrig, S.; Briquet, M.; Morel, T.; Schöller, M.; Gonzalez, Jorge Federico; De Cat, P.
Año de publicación
2008
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
θ Context. Carinae belongs to a group of peculiar early-type stars (OBN) with enhanced nitrogen and carbon deficiency. It is also known as a binary system, but it is not clear yet whether the chemical anomalies can be explained by mass transfer between the two components. On the basis of the previously reported spectral variability of a few metal lines it may be expected that Car possesses a weak magnetic field.Aims. A study of the physical nature of this hot massive binary which is furthermore a well-known blue straggler lying ~2 mag above the turnoff of the young open cluster IC 2602 is important to understand the origin of its strong chemical anomalies.Methods. We acquired high resolution spectroscopic and low resolution spectropolarimetric observations to achieve the following goals: a) to improve the orbital parameters to allow a more in-depth discussion on the possibility of mass transfer in the binary system; b) to carry out a non-local thermodynamic equilibrium (NLTE) abundance analysis; and c) to search for the presence of a magnetic field. Results. The study of the radial velocities using CORALIE spectra allowed us to significantly improve the orbital parameters. A comparative NLTE abundance analysis was undertaken for Car and two other early B-type stars with recently detected magnetic fields, τ Sco and ξ1 CMa. The analysis revealed significantly different abundance patterns: a one-order-of-magnitude nitrogen overabundance and carbon depletion was found in Car, while the oxygen abundance is roughly solar. For the stars ξ1 CMa and τ Sco the carbon abundance is solar and, while an N excess is also detected, it is of much smaller amplitude (0.4-0.6 dex). Such an N overabundance is typical of the values already found for other slowly-rotating (magnetic) B-type dwarfs. For Car, we attribute instead the chemical peculiarities to a past episode of mass transfer between the two binary components. The results of the search for a magnetic field using FORS 1 at the VLT consisting of 26 measurements over a time span of ~1.2 h are rather inconclusive: only few measurements have a significance level of 3. Although we detect a periodicity of the order of ~8.8 min in the dataset involving the measurements on all hydrogen Balmer lines with the exception of the Hα and H lines, these results have to be confirmed by additional time-resolved magnetic field observations.
Fil: Hubrig, S.. European Southern Observatory Chile; Chile
Fil: Briquet, M.. Katholieke Universiteit Leuven; Bélgica
Fil: Morel, T.. Katholieke Universiteit Leuven; Bélgica. Université de Liège; Bélgica
Fil: Schöller, M.. European Southern Observatory Chile; Chile
Fil: Gonzalez, Jorge Federico. 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. 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
Fil: De Cat, P.. Koninklijke Sterrenwacht van België; Bélgica
Materia
STARS: ABUNDANCES
STARS: ATMOSPHERES
STARS: BINARIES: SPECTROSCOPIC
STARS: EARLY-TYPE
STARS: FUNDAMENTAL PARAMETERS
STARS: MAGNETIC FIELDS
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:11336/214862

id CONICETDig_801773ec1d3b54a6d2232ceb93a6cbc9
oai_identifier_str oai:ri.conicet.gov.ar:11336/214862
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling New insights into the nature of the peculiar star θ CarinaeHubrig, S.Briquet, M.Morel, T.Schöller, M.Gonzalez, Jorge FedericoDe Cat, P.STARS: ABUNDANCESSTARS: ATMOSPHERESSTARS: BINARIES: SPECTROSCOPICSTARS: EARLY-TYPESTARS: FUNDAMENTAL PARAMETERSSTARS: MAGNETIC FIELDShttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1θ Context. Carinae belongs to a group of peculiar early-type stars (OBN) with enhanced nitrogen and carbon deficiency. It is also known as a binary system, but it is not clear yet whether the chemical anomalies can be explained by mass transfer between the two components. On the basis of the previously reported spectral variability of a few metal lines it may be expected that Car possesses a weak magnetic field.Aims. A study of the physical nature of this hot massive binary which is furthermore a well-known blue straggler lying ~2 mag above the turnoff of the young open cluster IC 2602 is important to understand the origin of its strong chemical anomalies.Methods. We acquired high resolution spectroscopic and low resolution spectropolarimetric observations to achieve the following goals: a) to improve the orbital parameters to allow a more in-depth discussion on the possibility of mass transfer in the binary system; b) to carry out a non-local thermodynamic equilibrium (NLTE) abundance analysis; and c) to search for the presence of a magnetic field. Results. The study of the radial velocities using CORALIE spectra allowed us to significantly improve the orbital parameters. A comparative NLTE abundance analysis was undertaken for Car and two other early B-type stars with recently detected magnetic fields, τ Sco and ξ1 CMa. The analysis revealed significantly different abundance patterns: a one-order-of-magnitude nitrogen overabundance and carbon depletion was found in Car, while the oxygen abundance is roughly solar. For the stars ξ1 CMa and τ Sco the carbon abundance is solar and, while an N excess is also detected, it is of much smaller amplitude (0.4-0.6 dex). Such an N overabundance is typical of the values already found for other slowly-rotating (magnetic) B-type dwarfs. For Car, we attribute instead the chemical peculiarities to a past episode of mass transfer between the two binary components. The results of the search for a magnetic field using FORS 1 at the VLT consisting of 26 measurements over a time span of ~1.2 h are rather inconclusive: only few measurements have a significance level of 3. Although we detect a periodicity of the order of ~8.8 min in the dataset involving the measurements on all hydrogen Balmer lines with the exception of the Hα and H lines, these results have to be confirmed by additional time-resolved magnetic field observations.Fil: Hubrig, S.. European Southern Observatory Chile; ChileFil: Briquet, M.. Katholieke Universiteit Leuven; BélgicaFil: Morel, T.. Katholieke Universiteit Leuven; Bélgica. Université de Liège; BélgicaFil: Schöller, M.. European Southern Observatory Chile; ChileFil: Gonzalez, Jorge Federico. 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. 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"; ArgentinaFil: De Cat, P.. Koninklijke Sterrenwacht van België; BélgicaEDP Sciences2008-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/octet-streamapplication/pdfhttp://hdl.handle.net/11336/214862Hubrig, S.; Briquet, M.; Morel, T.; Schöller, M.; Gonzalez, Jorge Federico; et al.; New insights into the nature of the peculiar star θ Carinae; EDP Sciences; Astronomy and Astrophysics; 488; 1; 12-2008; 287-2960004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:200809972info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2008/34/aa09972-08/aa09972-08.htmlinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:10:40Zoai:ri.conicet.gov.ar:11336/214862instacron: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 10:10:40.415CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv New insights into the nature of the peculiar star θ Carinae
title New insights into the nature of the peculiar star θ Carinae
spellingShingle New insights into the nature of the peculiar star θ Carinae
Hubrig, S.
STARS: ABUNDANCES
STARS: ATMOSPHERES
STARS: BINARIES: SPECTROSCOPIC
STARS: EARLY-TYPE
STARS: FUNDAMENTAL PARAMETERS
STARS: MAGNETIC FIELDS
title_short New insights into the nature of the peculiar star θ Carinae
title_full New insights into the nature of the peculiar star θ Carinae
title_fullStr New insights into the nature of the peculiar star θ Carinae
title_full_unstemmed New insights into the nature of the peculiar star θ Carinae
title_sort New insights into the nature of the peculiar star θ Carinae
dc.creator.none.fl_str_mv Hubrig, S.
Briquet, M.
Morel, T.
Schöller, M.
Gonzalez, Jorge Federico
De Cat, P.
author Hubrig, S.
author_facet Hubrig, S.
Briquet, M.
Morel, T.
Schöller, M.
Gonzalez, Jorge Federico
De Cat, P.
author_role author
author2 Briquet, M.
Morel, T.
Schöller, M.
Gonzalez, Jorge Federico
De Cat, P.
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv STARS: ABUNDANCES
STARS: ATMOSPHERES
STARS: BINARIES: SPECTROSCOPIC
STARS: EARLY-TYPE
STARS: FUNDAMENTAL PARAMETERS
STARS: MAGNETIC FIELDS
topic STARS: ABUNDANCES
STARS: ATMOSPHERES
STARS: BINARIES: SPECTROSCOPIC
STARS: EARLY-TYPE
STARS: FUNDAMENTAL PARAMETERS
STARS: MAGNETIC FIELDS
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv θ Context. Carinae belongs to a group of peculiar early-type stars (OBN) with enhanced nitrogen and carbon deficiency. It is also known as a binary system, but it is not clear yet whether the chemical anomalies can be explained by mass transfer between the two components. On the basis of the previously reported spectral variability of a few metal lines it may be expected that Car possesses a weak magnetic field.Aims. A study of the physical nature of this hot massive binary which is furthermore a well-known blue straggler lying ~2 mag above the turnoff of the young open cluster IC 2602 is important to understand the origin of its strong chemical anomalies.Methods. We acquired high resolution spectroscopic and low resolution spectropolarimetric observations to achieve the following goals: a) to improve the orbital parameters to allow a more in-depth discussion on the possibility of mass transfer in the binary system; b) to carry out a non-local thermodynamic equilibrium (NLTE) abundance analysis; and c) to search for the presence of a magnetic field. Results. The study of the radial velocities using CORALIE spectra allowed us to significantly improve the orbital parameters. A comparative NLTE abundance analysis was undertaken for Car and two other early B-type stars with recently detected magnetic fields, τ Sco and ξ1 CMa. The analysis revealed significantly different abundance patterns: a one-order-of-magnitude nitrogen overabundance and carbon depletion was found in Car, while the oxygen abundance is roughly solar. For the stars ξ1 CMa and τ Sco the carbon abundance is solar and, while an N excess is also detected, it is of much smaller amplitude (0.4-0.6 dex). Such an N overabundance is typical of the values already found for other slowly-rotating (magnetic) B-type dwarfs. For Car, we attribute instead the chemical peculiarities to a past episode of mass transfer between the two binary components. The results of the search for a magnetic field using FORS 1 at the VLT consisting of 26 measurements over a time span of ~1.2 h are rather inconclusive: only few measurements have a significance level of 3. Although we detect a periodicity of the order of ~8.8 min in the dataset involving the measurements on all hydrogen Balmer lines with the exception of the Hα and H lines, these results have to be confirmed by additional time-resolved magnetic field observations.
Fil: Hubrig, S.. European Southern Observatory Chile; Chile
Fil: Briquet, M.. Katholieke Universiteit Leuven; Bélgica
Fil: Morel, T.. Katholieke Universiteit Leuven; Bélgica. Université de Liège; Bélgica
Fil: Schöller, M.. European Southern Observatory Chile; Chile
Fil: Gonzalez, Jorge Federico. 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. 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
Fil: De Cat, P.. Koninklijke Sterrenwacht van België; Bélgica
description θ Context. Carinae belongs to a group of peculiar early-type stars (OBN) with enhanced nitrogen and carbon deficiency. It is also known as a binary system, but it is not clear yet whether the chemical anomalies can be explained by mass transfer between the two components. On the basis of the previously reported spectral variability of a few metal lines it may be expected that Car possesses a weak magnetic field.Aims. A study of the physical nature of this hot massive binary which is furthermore a well-known blue straggler lying ~2 mag above the turnoff of the young open cluster IC 2602 is important to understand the origin of its strong chemical anomalies.Methods. We acquired high resolution spectroscopic and low resolution spectropolarimetric observations to achieve the following goals: a) to improve the orbital parameters to allow a more in-depth discussion on the possibility of mass transfer in the binary system; b) to carry out a non-local thermodynamic equilibrium (NLTE) abundance analysis; and c) to search for the presence of a magnetic field. Results. The study of the radial velocities using CORALIE spectra allowed us to significantly improve the orbital parameters. A comparative NLTE abundance analysis was undertaken for Car and two other early B-type stars with recently detected magnetic fields, τ Sco and ξ1 CMa. The analysis revealed significantly different abundance patterns: a one-order-of-magnitude nitrogen overabundance and carbon depletion was found in Car, while the oxygen abundance is roughly solar. For the stars ξ1 CMa and τ Sco the carbon abundance is solar and, while an N excess is also detected, it is of much smaller amplitude (0.4-0.6 dex). Such an N overabundance is typical of the values already found for other slowly-rotating (magnetic) B-type dwarfs. For Car, we attribute instead the chemical peculiarities to a past episode of mass transfer between the two binary components. The results of the search for a magnetic field using FORS 1 at the VLT consisting of 26 measurements over a time span of ~1.2 h are rather inconclusive: only few measurements have a significance level of 3. Although we detect a periodicity of the order of ~8.8 min in the dataset involving the measurements on all hydrogen Balmer lines with the exception of the Hα and H lines, these results have to be confirmed by additional time-resolved magnetic field observations.
publishDate 2008
dc.date.none.fl_str_mv 2008-12
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/11336/214862
Hubrig, S.; Briquet, M.; Morel, T.; Schöller, M.; Gonzalez, Jorge Federico; et al.; New insights into the nature of the peculiar star θ Carinae; EDP Sciences; Astronomy and Astrophysics; 488; 1; 12-2008; 287-296
0004-6361
CONICET Digital
CONICET
url http://hdl.handle.net/11336/214862
identifier_str_mv Hubrig, S.; Briquet, M.; Morel, T.; Schöller, M.; Gonzalez, Jorge Federico; et al.; New insights into the nature of the peculiar star θ Carinae; EDP Sciences; Astronomy and Astrophysics; 488; 1; 12-2008; 287-296
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/10.1051/0004-6361:200809972
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/abs/2008/34/aa09972-08/aa09972-08.html
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/octet-stream
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
_version_ 1844613997830078464
score 13.070432