Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2

Autores
Roman Lopes, A.; Barba, Rodolfo Hector; Morrell, Nidia Irene
Año de publicación
2011
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
In this paper we report the identification of two new Galactic O2 If*/WN6 stars (WR20aa and WR20c), on the outskirts of the massive young stellar cluster Westerlund 2. The morphological similarity between the near-infrared spectra of the new stars with that of WR20a and WR21a (two of the most massive binaries known to date) is remarkable, indicating that probably they are also very massive stars. New optical spectroscopic observations of WR20aa suggest an intermediate O2 If*/WN6 spectral type. Based on a mosaic made from the 3.6 μm Spitzer IRAC images of the region including part of the RCW49 complex, we studied the spatial location of the new emission line stars, finding that WR20aa and WR20c are well displaced from the centre of Westerlund 2, being placed at ≈36 pc (15.7 arcmin) and ≈58 pc (25.0 arcmin), respectively, for an assumed heliocentric distance of 8 kpc. Also, very remarkably, a radius vector connecting the two stars would intercept the Westerlund 2 cluster exactly at the place where its stellar density reaches a maximum. We consequently postulate a scenario in which WR20aa and WR20c had a common origin somewhere in the cluster core, being ejected from their birthplace by dynamical interaction with some other very massive objects, perhaps during some earlier stage of the cluster evolution.
Fil: Roman Lopes, A.. Universidad de la Serena; Chile
Fil: Barba, Rodolfo Hector. Universidad de la Serena; Chile. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Juan. Instituto de Ciencias Astronomicas de la Tierra y del Espacio; Argentina
Fil: Morrell, Nidia Irene. Las Campanas Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; Argentina
Materia
WOLF-RAYET STARS
OPEN CLUSTERS
INFRARED STARS
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:11336/12981
Acceder
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oai_identifier_str oai:ri.conicet.gov.ar:11336/12981
network_acronym_str CONICETDig
repository_id_str 3498
network_name_str CONICET Digital (CONICET)
spelling Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2Roman Lopes, A.Barba, Rodolfo HectorMorrell, Nidia IreneWOLF-RAYET STARSOPEN CLUSTERSINFRARED STARShttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1In this paper we report the identification of two new Galactic O2 If*/WN6 stars (WR20aa and WR20c), on the outskirts of the massive young stellar cluster Westerlund 2. The morphological similarity between the near-infrared spectra of the new stars with that of WR20a and WR21a (two of the most massive binaries known to date) is remarkable, indicating that probably they are also very massive stars. New optical spectroscopic observations of WR20aa suggest an intermediate O2 If*/WN6 spectral type. Based on a mosaic made from the 3.6 μm Spitzer IRAC images of the region including part of the RCW49 complex, we studied the spatial location of the new emission line stars, finding that WR20aa and WR20c are well displaced from the centre of Westerlund 2, being placed at ≈36 pc (15.7 arcmin) and ≈58 pc (25.0 arcmin), respectively, for an assumed heliocentric distance of 8 kpc. Also, very remarkably, a radius vector connecting the two stars would intercept the Westerlund 2 cluster exactly at the place where its stellar density reaches a maximum. We consequently postulate a scenario in which WR20aa and WR20c had a common origin somewhere in the cluster core, being ejected from their birthplace by dynamical interaction with some other very massive objects, perhaps during some earlier stage of the cluster evolution.Fil: Roman Lopes, A.. Universidad de la Serena; ChileFil: Barba, Rodolfo Hector. Universidad de la Serena; Chile. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Juan. Instituto de Ciencias Astronomicas de la Tierra y del Espacio; ArgentinaFil: Morrell, Nidia Irene. Las Campanas Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; ArgentinaOxford University Press2011-09info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/12981Roman Lopes, A.; Barba, Rodolfo Hector; Morrell, Nidia Irene; Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2; Oxford University Press; Monthly Notices Of The Royal Astronomical Society; 416; 1; 9-2011; 501-5080035-8711enginfo:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-2966.2011.19062.xinfo:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/mnras/article-lookup/doi/10.1111/j.1365-2966.2011.19062.xinfo:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-10T13:06:25Zoai:ri.conicet.gov.ar:11336/12981instacron: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:34982025-09-10 13:06:25.88CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
title Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
spellingShingle Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
Roman Lopes, A.
WOLF-RAYET STARS
OPEN CLUSTERS
INFRARED STARS
title_short Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
title_full Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
title_fullStr Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
title_full_unstemmed Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
title_sort Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2
dc.creator.none.fl_str_mv Roman Lopes, A.
Barba, Rodolfo Hector
Morrell, Nidia Irene
author Roman Lopes, A.
author_facet Roman Lopes, A.
Barba, Rodolfo Hector
Morrell, Nidia Irene
author_role author
author2 Barba, Rodolfo Hector
Morrell, Nidia Irene
author2_role author
author
dc.subject.none.fl_str_mv WOLF-RAYET STARS
OPEN CLUSTERS
INFRARED STARS
topic WOLF-RAYET STARS
OPEN CLUSTERS
INFRARED STARS
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv In this paper we report the identification of two new Galactic O2 If*/WN6 stars (WR20aa and WR20c), on the outskirts of the massive young stellar cluster Westerlund 2. The morphological similarity between the near-infrared spectra of the new stars with that of WR20a and WR21a (two of the most massive binaries known to date) is remarkable, indicating that probably they are also very massive stars. New optical spectroscopic observations of WR20aa suggest an intermediate O2 If*/WN6 spectral type. Based on a mosaic made from the 3.6 μm Spitzer IRAC images of the region including part of the RCW49 complex, we studied the spatial location of the new emission line stars, finding that WR20aa and WR20c are well displaced from the centre of Westerlund 2, being placed at ≈36 pc (15.7 arcmin) and ≈58 pc (25.0 arcmin), respectively, for an assumed heliocentric distance of 8 kpc. Also, very remarkably, a radius vector connecting the two stars would intercept the Westerlund 2 cluster exactly at the place where its stellar density reaches a maximum. We consequently postulate a scenario in which WR20aa and WR20c had a common origin somewhere in the cluster core, being ejected from their birthplace by dynamical interaction with some other very massive objects, perhaps during some earlier stage of the cluster evolution.
Fil: Roman Lopes, A.. Universidad de la Serena; Chile
Fil: Barba, Rodolfo Hector. Universidad de la Serena; Chile. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico San Juan. Instituto de Ciencias Astronomicas de la Tierra y del Espacio; Argentina
Fil: Morrell, Nidia Irene. Las Campanas Observatory; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica de La Plata; Argentina
description In this paper we report the identification of two new Galactic O2 If*/WN6 stars (WR20aa and WR20c), on the outskirts of the massive young stellar cluster Westerlund 2. The morphological similarity between the near-infrared spectra of the new stars with that of WR20a and WR21a (two of the most massive binaries known to date) is remarkable, indicating that probably they are also very massive stars. New optical spectroscopic observations of WR20aa suggest an intermediate O2 If*/WN6 spectral type. Based on a mosaic made from the 3.6 μm Spitzer IRAC images of the region including part of the RCW49 complex, we studied the spatial location of the new emission line stars, finding that WR20aa and WR20c are well displaced from the centre of Westerlund 2, being placed at ≈36 pc (15.7 arcmin) and ≈58 pc (25.0 arcmin), respectively, for an assumed heliocentric distance of 8 kpc. Also, very remarkably, a radius vector connecting the two stars would intercept the Westerlund 2 cluster exactly at the place where its stellar density reaches a maximum. We consequently postulate a scenario in which WR20aa and WR20c had a common origin somewhere in the cluster core, being ejected from their birthplace by dynamical interaction with some other very massive objects, perhaps during some earlier stage of the cluster evolution.
publishDate 2011
dc.date.none.fl_str_mv 2011-09
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/11336/12981
Roman Lopes, A.; Barba, Rodolfo Hector; Morrell, Nidia Irene; Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2; Oxford University Press; Monthly Notices Of The Royal Astronomical Society; 416; 1; 9-2011; 501-508
0035-8711
url http://hdl.handle.net/11336/12981
identifier_str_mv Roman Lopes, A.; Barba, Rodolfo Hector; Morrell, Nidia Irene; Two O2 If*/WN6 stars possibly ejected from the massive young Galactic cluster Westerlund 2; Oxford University Press; Monthly Notices Of The Royal Astronomical Society; 416; 1; 9-2011; 501-508
0035-8711
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1111/j.1365-2966.2011.19062.x
info:eu-repo/semantics/altIdentifier/url/https://academic.oup.com/mnras/article-lookup/doi/10.1111/j.1365-2966.2011.19062.x
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 Oxford University Press
publisher.none.fl_str_mv Oxford University Press
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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score 12.993085

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