High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission

Autores
Arias, María Laura; Torres, Andrea Fabiana; Kraus, Michaela; Cidale, Lydia Sonia
Año de publicación
2026
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The post-main-sequence evolution of massive stars involves phases of intense, often eruptive mass loss, including the B[e] supergiant phase. These hot stars are surrounded by cool, dense circumstellar disks that host complex chemistry, producing both molecules and dust. Understanding the mass-loss history of B[e] supergiants is essential for constraining stellar evolution models, particularly regarding their final stages. Near- infrared CO band emission serves as a key tracer of disk dynamics, typically arising from the inner edge of the molecular disk or ring. However, the oxygen-rich environments of these stars also favor the presence of other molecules that trace regions complementary to those probed by CO. In this work, we present high-resolution near-infrared spectra of the Small Magellanic Cloud B[e] supergiant LHA 115-S 18. Our analysis reveals rotationally broadened CO emission consistent with a Keplerian molecular ring, alongside strong hydrogen wind features in both H and K bands and numerous metallic emission lines. Notably, we report the first detection of hot water vapor emission in a B[e] supergiant. This finding indicates the existence of extended cool and dense regions in a harsh environment. A radial velocity offset between molecular and Pfund line emission further supports a binary system, with the molecular gas potentially being circumbinary. The discovery of hot H2O around the B[e] supergiant star LHA 115-S 18 challenges classical models on the evolution and chemistry of massive binary stars and provides critical insight into mass-loss processes and molecular enrichment of the interstellar medium.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Circumstellar matter
B supergiant stars
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:10915/195666
Acceder
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network_name_str SEDICI (UNLP)
spelling High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor EmissionArias, María LauraTorres, Andrea FabianaKraus, MichaelaCidale, Lydia SoniaCiencias AstronómicasCircumstellar matterB supergiant starsThe post-main-sequence evolution of massive stars involves phases of intense, often eruptive mass loss, including the B[e] supergiant phase. These hot stars are surrounded by cool, dense circumstellar disks that host complex chemistry, producing both molecules and dust. Understanding the mass-loss history of B[e] supergiants is essential for constraining stellar evolution models, particularly regarding their final stages. Near- infrared CO band emission serves as a key tracer of disk dynamics, typically arising from the inner edge of the molecular disk or ring. However, the oxygen-rich environments of these stars also favor the presence of other molecules that trace regions complementary to those probed by CO. In this work, we present high-resolution near-infrared spectra of the Small Magellanic Cloud B[e] supergiant LHA 115-S 18. Our analysis reveals rotationally broadened CO emission consistent with a Keplerian molecular ring, alongside strong hydrogen wind features in both H and K bands and numerous metallic emission lines. Notably, we report the first detection of hot water vapor emission in a B[e] supergiant. This finding indicates the existence of extended cool and dense regions in a harsh environment. A radial velocity offset between molecular and Pfund line emission further supports a binary system, with the molecular gas potentially being circumbinary. The discovery of hot H2O around the B[e] supergiant star LHA 115-S 18 challenges classical models on the evolution and chemistry of massive binary stars and provides critical insight into mass-loss processes and molecular enrichment of the interstellar medium.Facultad de Ciencias Astronómicas y Geofísicas2026-03info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfhttp://sedici.unlp.edu.ar/handle/10915/195666enginfo:eu-repo/semantics/altIdentifier/issn/2041-8213info:eu-repo/semantics/altIdentifier/doi/10.3847/2041-8213/ae524ainfo: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:UNLP2026-06-23T11:17:11Zoai:sedici.unlp.edu.ar:10915/195666Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292026-06-23 11:17:11.821SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
title High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
spellingShingle High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
Arias, María Laura
Ciencias Astronómicas
Circumstellar matter
B supergiant stars
title_short High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
title_full High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
title_fullStr High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
title_full_unstemmed High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
title_sort High-resolution Near-Infrared Spectroscopy of the B[e] Supergiant LHA 115-S 18: Discovery of Hot Water Vapor Emission
dc.creator.none.fl_str_mv Arias, María Laura
Torres, Andrea Fabiana
Kraus, Michaela
Cidale, Lydia Sonia
author Arias, María Laura
author_facet Arias, María Laura
Torres, Andrea Fabiana
Kraus, Michaela
Cidale, Lydia Sonia
author_role author
author2 Torres, Andrea Fabiana
Kraus, Michaela
Cidale, Lydia Sonia
author2_role author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Circumstellar matter
B supergiant stars
topic Ciencias Astronómicas
Circumstellar matter
B supergiant stars
dc.description.none.fl_txt_mv The post-main-sequence evolution of massive stars involves phases of intense, often eruptive mass loss, including the B[e] supergiant phase. These hot stars are surrounded by cool, dense circumstellar disks that host complex chemistry, producing both molecules and dust. Understanding the mass-loss history of B[e] supergiants is essential for constraining stellar evolution models, particularly regarding their final stages. Near- infrared CO band emission serves as a key tracer of disk dynamics, typically arising from the inner edge of the molecular disk or ring. However, the oxygen-rich environments of these stars also favor the presence of other molecules that trace regions complementary to those probed by CO. In this work, we present high-resolution near-infrared spectra of the Small Magellanic Cloud B[e] supergiant LHA 115-S 18. Our analysis reveals rotationally broadened CO emission consistent with a Keplerian molecular ring, alongside strong hydrogen wind features in both H and K bands and numerous metallic emission lines. Notably, we report the first detection of hot water vapor emission in a B[e] supergiant. This finding indicates the existence of extended cool and dense regions in a harsh environment. A radial velocity offset between molecular and Pfund line emission further supports a binary system, with the molecular gas potentially being circumbinary. The discovery of hot H2O around the B[e] supergiant star LHA 115-S 18 challenges classical models on the evolution and chemistry of massive binary stars and provides critical insight into mass-loss processes and molecular enrichment of the interstellar medium.
Facultad de Ciencias Astronómicas y Geofísicas
description The post-main-sequence evolution of massive stars involves phases of intense, often eruptive mass loss, including the B[e] supergiant phase. These hot stars are surrounded by cool, dense circumstellar disks that host complex chemistry, producing both molecules and dust. Understanding the mass-loss history of B[e] supergiants is essential for constraining stellar evolution models, particularly regarding their final stages. Near- infrared CO band emission serves as a key tracer of disk dynamics, typically arising from the inner edge of the molecular disk or ring. However, the oxygen-rich environments of these stars also favor the presence of other molecules that trace regions complementary to those probed by CO. In this work, we present high-resolution near-infrared spectra of the Small Magellanic Cloud B[e] supergiant LHA 115-S 18. Our analysis reveals rotationally broadened CO emission consistent with a Keplerian molecular ring, alongside strong hydrogen wind features in both H and K bands and numerous metallic emission lines. Notably, we report the first detection of hot water vapor emission in a B[e] supergiant. This finding indicates the existence of extended cool and dense regions in a harsh environment. A radial velocity offset between molecular and Pfund line emission further supports a binary system, with the molecular gas potentially being circumbinary. The discovery of hot H2O around the B[e] supergiant star LHA 115-S 18 challenges classical models on the evolution and chemistry of massive binary stars and provides critical insight into mass-loss processes and molecular enrichment of the interstellar medium.
publishDate 2026
dc.date.none.fl_str_mv 2026-03
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
Articulo
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://sedici.unlp.edu.ar/handle/10915/195666
url http://sedici.unlp.edu.ar/handle/10915/195666
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/2041-8213
info:eu-repo/semantics/altIdentifier/doi/10.3847/2041-8213/ae524a
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
dc.source.none.fl_str_mv reponame:SEDICI (UNLP)
instname:Universidad Nacional de La Plata
instacron:UNLP
reponame_str SEDICI (UNLP)
collection SEDICI (UNLP)
instname_str Universidad Nacional de La Plata
instacron_str UNLP
institution UNLP
repository.name.fl_str_mv SEDICI (UNLP) - Universidad Nacional de La Plata
repository.mail.fl_str_mv alira@sedici.unlp.edu.ar
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