Testing the predicted mass-loss bi-stability jump at radio wavelengths

Autores
Benaglia, Paula; Vink, J. S.; Martí, J.; Maíz Apellániz, Jesús; Koribalski, B.; Crowther, P. A.
Año de publicación
2007
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Context. Massive stars play a dominant role in the Universe, but one of the main drivers for their evolution, their mass loss, remains poorly understood. Aims. In this study, we test the theoretically predicted mass-loss behaviour as a function of stellar effective temperature across the so-called "bi-stability" jump. Methods. We observe OB supergiants in the spectral range 08-B3 at radio wavelengths to measure their thermal radio flux densities, and complement these measurements with data from the literature. We derive the radio mass-loss rates and wind efficiencies, and compare our results with Hα- mass-loss rates and predictions based on radiation-driven wind models. Results. The wind efficiency shows the possible presence of a local maximum around an effective temperature of 21 000 K - in qualitative agreement with predictions. Furthermore, we find that the absolute values of the radio mass-loss rates show good agreement with empirical Hα rates derived assuming homogeneous winds - for the spectral range under consideration. However, the empirical mass-loss rates are larger (by a factor of a few) than the predicted rates from radiation-driven wind theory for objects above the bi-stability jump (BSJ) temperature, whilst they are smaller (by a factor of a few) for stars below the BSJ temperature. The reason for these discrepancies remains as yel unresolved. A new wind momenta-luminosity relation (WLR) for 08-B0 stars has been derived using the radio observations. The validity of the WLR as a function of the fitting parameter related to the force multiplier αeff (Kudritzki & Puls 2000) is discussed. Conclusions. Our most interesting finding is that the qualitative behaviour of the empirical wind efficiencies with effective temperature is in line with the predicted behaviour, and this presents the first hint of empirical evidence for the predicted mass-loss bi-stability jump. However, a larger sample of stars around the BSJ needs to be observed to confirm this finding.
Facultad de Ciencias Astronómicas y Geofísicas
Materia
Ciencias Astronómicas
Radio continuum: stars
Stars: early-type
Stars: mass-loss
Stars: winds, outflows
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:10915/83159

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oai_identifier_str oai:sedici.unlp.edu.ar:10915/83159
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Testing the predicted mass-loss bi-stability jump at radio wavelengthsBenaglia, PaulaVink, J. S.Martí, J.Maíz Apellániz, JesúsKoribalski, B.Crowther, P. A.Ciencias AstronómicasRadio continuum: starsStars: early-typeStars: mass-lossStars: winds, outflowsContext. Massive stars play a dominant role in the Universe, but one of the main drivers for their evolution, their mass loss, remains poorly understood. Aims. In this study, we test the theoretically predicted mass-loss behaviour as a function of stellar effective temperature across the so-called "bi-stability" jump. Methods. We observe OB supergiants in the spectral range 08-B3 at radio wavelengths to measure their thermal radio flux densities, and complement these measurements with data from the literature. We derive the radio mass-loss rates and wind efficiencies, and compare our results with Hα- mass-loss rates and predictions based on radiation-driven wind models. Results. The wind efficiency shows the possible presence of a local maximum around an effective temperature of 21 000 K - in qualitative agreement with predictions. Furthermore, we find that the absolute values of the radio mass-loss rates show good agreement with empirical Hα rates derived assuming homogeneous winds - for the spectral range under consideration. However, the empirical mass-loss rates are larger (by a factor of a few) than the predicted rates from radiation-driven wind theory for objects above the bi-stability jump (BSJ) temperature, whilst they are smaller (by a factor of a few) for stars below the BSJ temperature. The reason for these discrepancies remains as yel unresolved. A new wind momenta-luminosity relation (WLR) for 08-B0 stars has been derived using the radio observations. The validity of the WLR as a function of the fitting parameter related to the force multiplier αeff (Kudritzki & Puls 2000) is discussed. Conclusions. Our most interesting finding is that the qualitative behaviour of the empirical wind efficiencies with effective temperature is in line with the predicted behaviour, and this presents the first hint of empirical evidence for the predicted mass-loss bi-stability jump. However, a larger sample of stars around the BSJ needs to be observed to confirm this finding.Facultad de Ciencias Astronómicas y Geofísicas2007info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf1265-1274http://sedici.unlp.edu.ar/handle/10915/83159enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20077139info: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:UNLP2025-09-29T11:15:41Zoai:sedici.unlp.edu.ar:10915/83159Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:15:42.166SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Testing the predicted mass-loss bi-stability jump at radio wavelengths
title Testing the predicted mass-loss bi-stability jump at radio wavelengths
spellingShingle Testing the predicted mass-loss bi-stability jump at radio wavelengths
Benaglia, Paula
Ciencias Astronómicas
Radio continuum: stars
Stars: early-type
Stars: mass-loss
Stars: winds, outflows
title_short Testing the predicted mass-loss bi-stability jump at radio wavelengths
title_full Testing the predicted mass-loss bi-stability jump at radio wavelengths
title_fullStr Testing the predicted mass-loss bi-stability jump at radio wavelengths
title_full_unstemmed Testing the predicted mass-loss bi-stability jump at radio wavelengths
title_sort Testing the predicted mass-loss bi-stability jump at radio wavelengths
dc.creator.none.fl_str_mv Benaglia, Paula
Vink, J. S.
Martí, J.
Maíz Apellániz, Jesús
Koribalski, B.
Crowther, P. A.
author Benaglia, Paula
author_facet Benaglia, Paula
Vink, J. S.
Martí, J.
Maíz Apellániz, Jesús
Koribalski, B.
Crowther, P. A.
author_role author
author2 Vink, J. S.
Martí, J.
Maíz Apellániz, Jesús
Koribalski, B.
Crowther, P. A.
author2_role author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
Radio continuum: stars
Stars: early-type
Stars: mass-loss
Stars: winds, outflows
topic Ciencias Astronómicas
Radio continuum: stars
Stars: early-type
Stars: mass-loss
Stars: winds, outflows
dc.description.none.fl_txt_mv Context. Massive stars play a dominant role in the Universe, but one of the main drivers for their evolution, their mass loss, remains poorly understood. Aims. In this study, we test the theoretically predicted mass-loss behaviour as a function of stellar effective temperature across the so-called "bi-stability" jump. Methods. We observe OB supergiants in the spectral range 08-B3 at radio wavelengths to measure their thermal radio flux densities, and complement these measurements with data from the literature. We derive the radio mass-loss rates and wind efficiencies, and compare our results with Hα- mass-loss rates and predictions based on radiation-driven wind models. Results. The wind efficiency shows the possible presence of a local maximum around an effective temperature of 21 000 K - in qualitative agreement with predictions. Furthermore, we find that the absolute values of the radio mass-loss rates show good agreement with empirical Hα rates derived assuming homogeneous winds - for the spectral range under consideration. However, the empirical mass-loss rates are larger (by a factor of a few) than the predicted rates from radiation-driven wind theory for objects above the bi-stability jump (BSJ) temperature, whilst they are smaller (by a factor of a few) for stars below the BSJ temperature. The reason for these discrepancies remains as yel unresolved. A new wind momenta-luminosity relation (WLR) for 08-B0 stars has been derived using the radio observations. The validity of the WLR as a function of the fitting parameter related to the force multiplier αeff (Kudritzki & Puls 2000) is discussed. Conclusions. Our most interesting finding is that the qualitative behaviour of the empirical wind efficiencies with effective temperature is in line with the predicted behaviour, and this presents the first hint of empirical evidence for the predicted mass-loss bi-stability jump. However, a larger sample of stars around the BSJ needs to be observed to confirm this finding.
Facultad de Ciencias Astronómicas y Geofísicas
description Context. Massive stars play a dominant role in the Universe, but one of the main drivers for their evolution, their mass loss, remains poorly understood. Aims. In this study, we test the theoretically predicted mass-loss behaviour as a function of stellar effective temperature across the so-called "bi-stability" jump. Methods. We observe OB supergiants in the spectral range 08-B3 at radio wavelengths to measure their thermal radio flux densities, and complement these measurements with data from the literature. We derive the radio mass-loss rates and wind efficiencies, and compare our results with Hα- mass-loss rates and predictions based on radiation-driven wind models. Results. The wind efficiency shows the possible presence of a local maximum around an effective temperature of 21 000 K - in qualitative agreement with predictions. Furthermore, we find that the absolute values of the radio mass-loss rates show good agreement with empirical Hα rates derived assuming homogeneous winds - for the spectral range under consideration. However, the empirical mass-loss rates are larger (by a factor of a few) than the predicted rates from radiation-driven wind theory for objects above the bi-stability jump (BSJ) temperature, whilst they are smaller (by a factor of a few) for stars below the BSJ temperature. The reason for these discrepancies remains as yel unresolved. A new wind momenta-luminosity relation (WLR) for 08-B0 stars has been derived using the radio observations. The validity of the WLR as a function of the fitting parameter related to the force multiplier αeff (Kudritzki & Puls 2000) is discussed. Conclusions. Our most interesting finding is that the qualitative behaviour of the empirical wind efficiencies with effective temperature is in line with the predicted behaviour, and this presents the first hint of empirical evidence for the predicted mass-loss bi-stability jump. However, a larger sample of stars around the BSJ needs to be observed to confirm this finding.
publishDate 2007
dc.date.none.fl_str_mv 2007
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/10915/83159
url http://sedici.unlp.edu.ar/handle/10915/83159
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0004-6361
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:20077139
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
1265-1274
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instname:Universidad Nacional de La Plata
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reponame_str SEDICI (UNLP)
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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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