The Onfp class in the Magellanic Clouds

Autores
Walborn, Nolan Revere; Howarth, Ian D.; Evans, Christopher J.; Crowther, Paul A.; Moffat, Anthony F. J.; St-Louis, Nicole; Fariña, Cecilia; Bosch, Guillermo Luis; Morrell, Nidia Irene; Barbá, Rodolfo Héctor; Loon, Jacco T. van
Año de publicación
2010
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
The Onfp class of rotationally broadened, hot spectra was defined some time ago in the Galaxy, where its membership to date numbers only eight. The principal defining characteristic is a broad, centrally reversed He II λ 4686 emission profile; other emission and absorption lines are also rotationally broadened. Recent surveys in the Magellanic Clouds (MCs) have brought the class membership there, including some related spectra, to 28. We present a survey of the spectral morphology and rotational velocities, as a first step toward elucidating the nature of this class. Evolved, rapidly rotating hot stars are not expected theoretically, because the stellar winds should brake the rotation. Luminosity classification of these spectra is not possible, because the principal criterion (He II λ4686) is peculiar; however, the MCs provide reliable absolute magnitudes, which show that they span the entire range from dwarfs to supergiants. The Onfp line-broadening distribution is distinct and shifted toward larger values from those of normal O dwarfs and supergiants with >99.99% confidence. All cases with multiple observations show line-profile variations, which even remove some objects from the class temporarily. Some of them are spectroscopic binaries; it is possible that the peculiar profiles may have multiple causes among different objects. The origin and future of these stars are intriguing; for instance, they could be stellar mergers and/or gamma-ray-burst progenitors.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Magellanic Clouds
Stars: early-type
Stars: emission-line, Be
Stars: fundamental parameters
Stars: rotation
Stars: variables: general
Nivel de accesibilidad
acceso abierto
Condiciones de uso
http://creativecommons.org/licenses/by-nc-sa/4.0/
Repositorio
SEDICI (UNLP)
Institución
Universidad Nacional de La Plata
OAI Identificador
oai:sedici.unlp.edu.ar:10915/82516

id SEDICI_bfe944743b480ef2096e16b13fd9d80f
oai_identifier_str oai:sedici.unlp.edu.ar:10915/82516
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling The Onfp class in the Magellanic CloudsWalborn, Nolan RevereHowarth, Ian D.Evans, Christopher J.Crowther, Paul A.Moffat, Anthony F. J.St-Louis, NicoleFariña, CeciliaBosch, Guillermo LuisMorrell, Nidia IreneBarbá, Rodolfo HéctorLoon, Jacco T. vanCiencias AstronómicasMagellanic CloudsStars: early-typeStars: emission-line, BeStars: fundamental parametersStars: rotationStars: variables: generalThe Onfp class of rotationally broadened, hot spectra was defined some time ago in the Galaxy, where its membership to date numbers only eight. The principal defining characteristic is a broad, centrally reversed He II λ 4686 emission profile; other emission and absorption lines are also rotationally broadened. Recent surveys in the Magellanic Clouds (MCs) have brought the class membership there, including some related spectra, to 28. We present a survey of the spectral morphology and rotational velocities, as a first step toward elucidating the nature of this class. Evolved, rapidly rotating hot stars are not expected theoretically, because the stellar winds should brake the rotation. Luminosity classification of these spectra is not possible, because the principal criterion (He II λ4686) is peculiar; however, the MCs provide reliable absolute magnitudes, which show that they span the entire range from dwarfs to supergiants. The Onfp line-broadening distribution is distinct and shifted toward larger values from those of normal O dwarfs and supergiants with >99.99% confidence. All cases with multiple observations show line-profile variations, which even remove some objects from the class temporarily. Some of them are spectroscopic binaries; it is possible that the peculiar profiles may have multiple causes among different objects. The origin and future of these stars are intriguing; for instance, they could be stellar mergers and/or gamma-ray-burst progenitors.Facultad de Ciencias Astronómicas y Geofísicas2010info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1283-1294http://sedici.unlp.edu.ar/handle/10915/82516enginfo:eu-repo/semantics/altIdentifier/issn/00046256info:eu-repo/semantics/altIdentifier/doi/10.1088/0004-6256/139/3/1283info:eu-repo/semantics/openAccesshttp://creativecommons.org/licenses/by-nc-sa/4.0/Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)reponame:SEDICI (UNLP)instname:Universidad Nacional de La Platainstacron:UNLP2025-09-29T11:15:31Zoai:sedici.unlp.edu.ar:10915/82516Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:31.408SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv The Onfp class in the Magellanic Clouds
title The Onfp class in the Magellanic Clouds
spellingShingle The Onfp class in the Magellanic Clouds
Walborn, Nolan Revere
Ciencias Astronómicas
Magellanic Clouds
Stars: early-type
Stars: emission-line, Be
Stars: fundamental parameters
Stars: rotation
Stars: variables: general
title_short The Onfp class in the Magellanic Clouds
title_full The Onfp class in the Magellanic Clouds
title_fullStr The Onfp class in the Magellanic Clouds
title_full_unstemmed The Onfp class in the Magellanic Clouds
title_sort The Onfp class in the Magellanic Clouds
dc.creator.none.fl_str_mv Walborn, Nolan Revere
Howarth, Ian D.
Evans, Christopher J.
Crowther, Paul A.
Moffat, Anthony F. J.
St-Louis, Nicole
Fariña, Cecilia
Bosch, Guillermo Luis
Morrell, Nidia Irene
Barbá, Rodolfo Héctor
Loon, Jacco T. van
author Walborn, Nolan Revere
author_facet Walborn, Nolan Revere
Howarth, Ian D.
Evans, Christopher J.
Crowther, Paul A.
Moffat, Anthony F. J.
St-Louis, Nicole
Fariña, Cecilia
Bosch, Guillermo Luis
Morrell, Nidia Irene
Barbá, Rodolfo Héctor
Loon, Jacco T. van
author_role author
author2 Howarth, Ian D.
Evans, Christopher J.
Crowther, Paul A.
Moffat, Anthony F. J.
St-Louis, Nicole
Fariña, Cecilia
Bosch, Guillermo Luis
Morrell, Nidia Irene
Barbá, Rodolfo Héctor
Loon, Jacco T. van
author2_role author
author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Magellanic Clouds
Stars: early-type
Stars: emission-line, Be
Stars: fundamental parameters
Stars: rotation
Stars: variables: general
topic Ciencias Astronómicas
Magellanic Clouds
Stars: early-type
Stars: emission-line, Be
Stars: fundamental parameters
Stars: rotation
Stars: variables: general
dc.description.none.fl_txt_mv The Onfp class of rotationally broadened, hot spectra was defined some time ago in the Galaxy, where its membership to date numbers only eight. The principal defining characteristic is a broad, centrally reversed He II λ 4686 emission profile; other emission and absorption lines are also rotationally broadened. Recent surveys in the Magellanic Clouds (MCs) have brought the class membership there, including some related spectra, to 28. We present a survey of the spectral morphology and rotational velocities, as a first step toward elucidating the nature of this class. Evolved, rapidly rotating hot stars are not expected theoretically, because the stellar winds should brake the rotation. Luminosity classification of these spectra is not possible, because the principal criterion (He II λ4686) is peculiar; however, the MCs provide reliable absolute magnitudes, which show that they span the entire range from dwarfs to supergiants. The Onfp line-broadening distribution is distinct and shifted toward larger values from those of normal O dwarfs and supergiants with >99.99% confidence. All cases with multiple observations show line-profile variations, which even remove some objects from the class temporarily. Some of them are spectroscopic binaries; it is possible that the peculiar profiles may have multiple causes among different objects. The origin and future of these stars are intriguing; for instance, they could be stellar mergers and/or gamma-ray-burst progenitors.
Facultad de Ciencias Astronómicas y Geofísicas
description The Onfp class of rotationally broadened, hot spectra was defined some time ago in the Galaxy, where its membership to date numbers only eight. The principal defining characteristic is a broad, centrally reversed He II λ 4686 emission profile; other emission and absorption lines are also rotationally broadened. Recent surveys in the Magellanic Clouds (MCs) have brought the class membership there, including some related spectra, to 28. We present a survey of the spectral morphology and rotational velocities, as a first step toward elucidating the nature of this class. Evolved, rapidly rotating hot stars are not expected theoretically, because the stellar winds should brake the rotation. Luminosity classification of these spectra is not possible, because the principal criterion (He II λ4686) is peculiar; however, the MCs provide reliable absolute magnitudes, which show that they span the entire range from dwarfs to supergiants. The Onfp line-broadening distribution is distinct and shifted toward larger values from those of normal O dwarfs and supergiants with >99.99% confidence. All cases with multiple observations show line-profile variations, which even remove some objects from the class temporarily. Some of them are spectroscopic binaries; it is possible that the peculiar profiles may have multiple causes among different objects. The origin and future of these stars are intriguing; for instance, they could be stellar mergers and/or gamma-ray-burst progenitors.
publishDate 2010
dc.date.none.fl_str_mv 2010
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/10915/82516
url http://sedici.unlp.edu.ar/handle/10915/82516
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/00046256
info:eu-repo/semantics/altIdentifier/doi/10.1088/0004-6256/139/3/1283
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
eu_rights_str_mv openAccess
rights_invalid_str_mv http://creativecommons.org/licenses/by-nc-sa/4.0/
Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
dc.format.none.fl_str_mv application/pdf
1283-1294
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
_version_ 1844616027084685312
score 13.070432