Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies
- Autores
- Zorec, Juan; Frémat, Y.; Domiciano de Souza, A.; Delaa, O.; Stee, P.; Mourard, D.; Cidale, Lydia Sonia; Martayan, C.; Georgy, C.; Ekström, S.
- Año de publicación
- 2011
- Idioma
- inglés
- Tipo de recurso
- artículo
- Estado
- versión publicada
- Descripción
- Context. Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. Aims. We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods. Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible differential rotations in the envelope of early-type stars. A surface latitudinal differential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution. Results. By studying the equation of the surface of stars with non-conservative rotation laws, we conclude that objects undergo geometrical deformations that are a function of the latitudinal differential rotation able to be scrutinized both spectroscopically and by interferometry. The combination of Fourier analysis of spectral lines with model atmospheres provides independent estimates of the surface latitudinal differential rotation and the inclination angle. Models of stars at different evolutionary stages rotating with internal conservative rotation laws were calculated to show that the Roche approximation can be safely used to account for the gravitational potential. The surface temperature gradient in rapid rotators induce an acceleration to the surface angular velocity. Although a non-zero differential rotation parameter may indicate that the rotation is neither rigid nor shellular underneath the stellar surface, still further information, perhaps non-radial pulsations, is needed to determine its characteristics as a function of depth.
Facultad de Ciencias Astronómicas y Geofísicas
Instituto de Astrofísica de La Plata - Materia
-
Ciencias Astronómicas
stars: early-type
stars: massive
stars: rotation
techniques: interferometric
techniques: spectroscopic - Nivel de accesibilidad
- acceso abierto
- Condiciones de uso
- http://creativecommons.org/licenses/by-nc-sa/4.0/
- Repositorio
- Institución
- Universidad Nacional de La Plata
- OAI Identificador
- oai:sedici.unlp.edu.ar:10915/84140
Ver los metadatos del registro completo
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Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studiesZorec, JuanFrémat, Y.Domiciano de Souza, A.Delaa, O.Stee, P.Mourard, D.Cidale, Lydia SoniaMartayan, C.Georgy, C.Ekström, S.Ciencias Astronómicasstars: early-typestars: massivestars: rotationtechniques: interferometrictechniques: spectroscopicContext. Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. Aims. We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods. Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible differential rotations in the envelope of early-type stars. A surface latitudinal differential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution. Results. By studying the equation of the surface of stars with non-conservative rotation laws, we conclude that objects undergo geometrical deformations that are a function of the latitudinal differential rotation able to be scrutinized both spectroscopically and by interferometry. The combination of Fourier analysis of spectral lines with model atmospheres provides independent estimates of the surface latitudinal differential rotation and the inclination angle. Models of stars at different evolutionary stages rotating with internal conservative rotation laws were calculated to show that the Roche approximation can be safely used to account for the gravitational potential. The surface temperature gradient in rapid rotators induce an acceleration to the surface angular velocity. Although a non-zero differential rotation parameter may indicate that the rotation is neither rigid nor shellular underneath the stellar surface, still further information, perhaps non-radial pulsations, is needed to determine its characteristics as a function of depth.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plata2011info: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/10915/84140enginfo:eu-repo/semantics/altIdentifier/issn/0004-6361info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201015691info: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:UNLP2025-09-29T11:16:10Zoai:sedici.unlp.edu.ar:10915/84140Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:16:10.353SEDICI (UNLP) - Universidad Nacional de La Platafalse |
dc.title.none.fl_str_mv |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
title |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
spellingShingle |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies Zorec, Juan Ciencias Astronómicas stars: early-type stars: massive stars: rotation techniques: interferometric techniques: spectroscopic |
title_short |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
title_full |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
title_fullStr |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
title_full_unstemmed |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
title_sort |
Differential rotation in rapidly rotating early-type stars : I. Motivations for combined spectroscopic and interferometric studies |
dc.creator.none.fl_str_mv |
Zorec, Juan Frémat, Y. Domiciano de Souza, A. Delaa, O. Stee, P. Mourard, D. Cidale, Lydia Sonia Martayan, C. Georgy, C. Ekström, S. |
author |
Zorec, Juan |
author_facet |
Zorec, Juan Frémat, Y. Domiciano de Souza, A. Delaa, O. Stee, P. Mourard, D. Cidale, Lydia Sonia Martayan, C. Georgy, C. Ekström, S. |
author_role |
author |
author2 |
Frémat, Y. Domiciano de Souza, A. Delaa, O. Stee, P. Mourard, D. Cidale, Lydia Sonia Martayan, C. Georgy, C. Ekström, S. |
author2_role |
author author author author author author author author author |
dc.subject.none.fl_str_mv |
Ciencias Astronómicas stars: early-type stars: massive stars: rotation techniques: interferometric techniques: spectroscopic |
topic |
Ciencias Astronómicas stars: early-type stars: massive stars: rotation techniques: interferometric techniques: spectroscopic |
dc.description.none.fl_txt_mv |
Context. Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. Aims. We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods. Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible differential rotations in the envelope of early-type stars. A surface latitudinal differential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution. Results. By studying the equation of the surface of stars with non-conservative rotation laws, we conclude that objects undergo geometrical deformations that are a function of the latitudinal differential rotation able to be scrutinized both spectroscopically and by interferometry. The combination of Fourier analysis of spectral lines with model atmospheres provides independent estimates of the surface latitudinal differential rotation and the inclination angle. Models of stars at different evolutionary stages rotating with internal conservative rotation laws were calculated to show that the Roche approximation can be safely used to account for the gravitational potential. The surface temperature gradient in rapid rotators induce an acceleration to the surface angular velocity. Although a non-zero differential rotation parameter may indicate that the rotation is neither rigid nor shellular underneath the stellar surface, still further information, perhaps non-radial pulsations, is needed to determine its characteristics as a function of depth. Facultad de Ciencias Astronómicas y Geofísicas Instituto de Astrofísica de La Plata |
description |
Context. Since the external regions of the envelopes of rapidly rotating early-type stars are unstable to convection, a coupling may exist between the convection and the internal rotation. Aims. We explore what can be learned from spectroscopic and interferometric observations about the properties of the rotation law in the external layers of these objects. Methods. Using simple relations between the entropy and specific rotational quantities, some of which are found to be efficient at accounting for the solar differential rotation in the convective region, we derived analytical solutions that represent possible differential rotations in the envelope of early-type stars. A surface latitudinal differential rotation may not only be an external imprint of the inner rotation, but induces changes in the stellar geometry, the gravitational darkening, the aspect of spectral line profiles, and the emitted spectral energy distribution. Results. By studying the equation of the surface of stars with non-conservative rotation laws, we conclude that objects undergo geometrical deformations that are a function of the latitudinal differential rotation able to be scrutinized both spectroscopically and by interferometry. The combination of Fourier analysis of spectral lines with model atmospheres provides independent estimates of the surface latitudinal differential rotation and the inclination angle. Models of stars at different evolutionary stages rotating with internal conservative rotation laws were calculated to show that the Roche approximation can be safely used to account for the gravitational potential. The surface temperature gradient in rapid rotators induce an acceleration to the surface angular velocity. Although a non-zero differential rotation parameter may indicate that the rotation is neither rigid nor shellular underneath the stellar surface, still further information, perhaps non-radial pulsations, is needed to determine its characteristics as a function of depth. |
publishDate |
2011 |
dc.date.none.fl_str_mv |
2011 |
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http://sedici.unlp.edu.ar/handle/10915/84140 |
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eng |
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eng |
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info:eu-repo/semantics/altIdentifier/issn/0004-6361 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201015691 |
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