The distance to the young open cluster Westerlund 2
- Autores
- Carraro, G.; Turner, D.; Majaess, D.; Baume, Gustavo Luis
- Año de publicación
- 2013
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- A new X-ray, UBVRIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster’s distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation toward Westerlund 2 described by EU−B/EB−V = 0.63 + 0.02 EB−V . Variable-extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of RV = AV/EB−V = 3.88±0.18 and 3.77±0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina. The results were confirmed by applying the color-difference method to UBVRIcJHKs data for 19 spectroscopically observed cluster members, yielding RV = 3.85 ± 0.07. The derived distance to Westerlund 2 of d = 2.85 ± 0.43 kpc places the cluster on the far side of the Carina spiral arm. The cluster’s age is no more than τ ∼ 2 × 106 yr as inferred from the cluster’s brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are very likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color–magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5 V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. These features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of γ-rays, cosmic rays, and X-rays from the direction toward Westerlund 2.
Fil: Carraro, G.. Observatorio Europeo Austral; Chile;
Fil: Turner, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá;
Fil: Majaess, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá;
Fil: Baume, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica La Plata; Argentina; - Materia
-
Open clusters and associations
Wolf-Rayet
H ii regions
Westerlund 2 - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- https://creativecommons.org/licenses/by-nc/2.5/ar/
- Repositorio
- Institución
- Consejo Nacional de Investigaciones Científicas y Técnicas
- OAI Identificador
- oai:ri.conicet.gov.ar:11336/2430
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The distance to the young open cluster Westerlund 2Carraro, G.Turner, D.Majaess, D.Baume, Gustavo LuisOpen clusters and associationsWolf-RayetH ii regionsWesterlund 2https://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1A new X-ray, UBVRIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster’s distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation toward Westerlund 2 described by EU−B/EB−V = 0.63 + 0.02 EB−V . Variable-extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of RV = AV/EB−V = 3.88±0.18 and 3.77±0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina. The results were confirmed by applying the color-difference method to UBVRIcJHKs data for 19 spectroscopically observed cluster members, yielding RV = 3.85 ± 0.07. The derived distance to Westerlund 2 of d = 2.85 ± 0.43 kpc places the cluster on the far side of the Carina spiral arm. The cluster’s age is no more than τ ∼ 2 × 106 yr as inferred from the cluster’s brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are very likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color–magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5 V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. These features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of γ-rays, cosmic rays, and X-rays from the direction toward Westerlund 2.Fil: Carraro, G.. Observatorio Europeo Austral; Chile;Fil: Turner, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá;Fil: Majaess, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá;Fil: Baume, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica La Plata; Argentina;EDP Sciences2013-07info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/2430Carraro, G.; Turner, D.; Majaess, D.; Baume, Gustavo Luis; The distance to the young open cluster Westerlund 2; EDP Sciences; Astronomy & Astrophysics; 555; A50; 7-2013; 1-90004-6361enginfo:eu-repo/semantics/altIdentifier/url/http://www.aanda.org/articles/aa/abs/2013/07/aa21421-13/aa21421-13.htmlinfo:eu-repo/semantics/altIdentifier/url/http://arxiv.org/abs/1305.4309info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201321421info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-10-15T14:22:17Zoai:ri.conicet.gov.ar:11336/2430instacron: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:34982025-10-15 14:22:17.841CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse |
dc.title.none.fl_str_mv |
The distance to the young open cluster Westerlund 2 |
title |
The distance to the young open cluster Westerlund 2 |
spellingShingle |
The distance to the young open cluster Westerlund 2 Carraro, G. Open clusters and associations Wolf-Rayet H ii regions Westerlund 2 |
title_short |
The distance to the young open cluster Westerlund 2 |
title_full |
The distance to the young open cluster Westerlund 2 |
title_fullStr |
The distance to the young open cluster Westerlund 2 |
title_full_unstemmed |
The distance to the young open cluster Westerlund 2 |
title_sort |
The distance to the young open cluster Westerlund 2 |
dc.creator.none.fl_str_mv |
Carraro, G. Turner, D. Majaess, D. Baume, Gustavo Luis |
author |
Carraro, G. |
author_facet |
Carraro, G. Turner, D. Majaess, D. Baume, Gustavo Luis |
author_role |
author |
author2 |
Turner, D. Majaess, D. Baume, Gustavo Luis |
author2_role |
author author author |
dc.subject.none.fl_str_mv |
Open clusters and associations Wolf-Rayet H ii regions Westerlund 2 |
topic |
Open clusters and associations Wolf-Rayet H ii regions Westerlund 2 |
purl_subject.fl_str_mv |
https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
dc.description.none.fl_txt_mv |
A new X-ray, UBVRIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster’s distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation toward Westerlund 2 described by EU−B/EB−V = 0.63 + 0.02 EB−V . Variable-extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of RV = AV/EB−V = 3.88±0.18 and 3.77±0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina. The results were confirmed by applying the color-difference method to UBVRIcJHKs data for 19 spectroscopically observed cluster members, yielding RV = 3.85 ± 0.07. The derived distance to Westerlund 2 of d = 2.85 ± 0.43 kpc places the cluster on the far side of the Carina spiral arm. The cluster’s age is no more than τ ∼ 2 × 106 yr as inferred from the cluster’s brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are very likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color–magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5 V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. These features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of γ-rays, cosmic rays, and X-rays from the direction toward Westerlund 2. Fil: Carraro, G.. Observatorio Europeo Austral; Chile; Fil: Turner, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá; Fil: Majaess, D.. Saint Mary’s University. Department of Astronomy and Physics; Canadá; Fil: Baume, Gustavo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Instituto de Astrofísica La Plata; Argentina; |
description |
A new X-ray, UBVRIc, and JHKs study of the young cluster Westerlund 2 was undertaken to resolve discrepancies tied to the cluster’s distance. Existing spectroscopic observations for bright cluster members and new multi-band photometry imply a reddening relation toward Westerlund 2 described by EU−B/EB−V = 0.63 + 0.02 EB−V . Variable-extinction analyses for Westerlund 2 and nearby IC 2581 based upon spectroscopic distance moduli and ZAMS fitting yield values of RV = AV/EB−V = 3.88±0.18 and 3.77±0.19, respectively, and confirm prior assertions that anomalous interstellar extinction is widespread throughout Carina. The results were confirmed by applying the color-difference method to UBVRIcJHKs data for 19 spectroscopically observed cluster members, yielding RV = 3.85 ± 0.07. The derived distance to Westerlund 2 of d = 2.85 ± 0.43 kpc places the cluster on the far side of the Carina spiral arm. The cluster’s age is no more than τ ∼ 2 × 106 yr as inferred from the cluster’s brightest stars and an X-ray (Chandra) cleaned analysis of its pre-main-sequence demographic. Four Wolf-Rayet stars in the cluster core and surrounding corona (WR20a, WR20b, WR20c, and WR20aa) are very likely cluster members, and their inferred luminosities are consistent with those of other late-WN stars in open clusters. The color–magnitude diagram for Westerlund 2 also displays a gap at spectral type B0.5 V with associated color spread at higher and lower absolute magnitudes that might be linked to close binary mergers. These features, in conjunction with the evidence for mass loss from the WR stars, may help to explain the high flux of γ-rays, cosmic rays, and X-rays from the direction toward Westerlund 2. |
publishDate |
2013 |
dc.date.none.fl_str_mv |
2013-07 |
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/11336/2430 Carraro, G.; Turner, D.; Majaess, D.; Baume, Gustavo Luis; The distance to the young open cluster Westerlund 2; EDP Sciences; Astronomy & Astrophysics; 555; A50; 7-2013; 1-9 0004-6361 |
url |
http://hdl.handle.net/11336/2430 |
identifier_str_mv |
Carraro, G.; Turner, D.; Majaess, D.; Baume, Gustavo Luis; The distance to the young open cluster Westerlund 2; EDP Sciences; Astronomy & Astrophysics; 555; A50; 7-2013; 1-9 0004-6361 |
dc.language.none.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
info:eu-repo/semantics/altIdentifier/url/http://www.aanda.org/articles/aa/abs/2013/07/aa21421-13/aa21421-13.html info:eu-repo/semantics/altIdentifier/url/http://arxiv.org/abs/1305.4309 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201321421 |
dc.rights.none.fl_str_mv |
info:eu-repo/semantics/openAccess https://creativecommons.org/licenses/by-nc/2.5/ar/ |
eu_rights_str_mv |
openAccess |
rights_invalid_str_mv |
https://creativecommons.org/licenses/by-nc/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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13.22299 |