Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561

Autores
Wade, G. A.; Barbá, Rodolfo Héctor; Grunhut, J.; Martins, F.; Petit, V.; Sundqvist, J. O.; Townsend, R. H. D.; Walborn, N. R.; Alecian, E.; Alfaro, E. J.; Maíz Apellániz, J.; Arias, Julia Inés; Gamen, Roberto Claudio; Morrell, Nidia Irene; Nazé, Y.; Sota, A.; Doula, A. ud; MiMeS Collaboration
Año de publicación
2015
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
We report magnetic and spectroscopic observations and modelling of the Of?p star CPD-28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and wind-sensitive spectral lines. A period search results in an unambiguous 73.41 d variability period. High-resolution spectropolarimetric data analysed using least-squares deconvolution yield a Zeeman signature detected in the mean Stokes V profile corresponding to phase 0.5 of the spectral ephemeris. Interpreting the 73.41 d period as the stellar rotational period, we have phased the equivalent widths and inferred longitudinal field measurements. The phased magnetic data exhibit a weak sinusoidal variation, with maximum of about 565 G at phase 0.5, and a minimum of about -335 G at phase 0.0, with extrema approximately in phase with the (double-wave) Hα equivalent width variation. Modelling of the Hα equivalent width variation assuming a quasi-3D magnetospheric model produces a unique solution for the ambiguous couplet of inclination and magnetic obliquity angles: (i, β) or (β, i) = (35°, 90°). Adopting either geometry, the longitudinal field variation yields a dipole polar intensity Bd = 2.6 ± 0.9 kG, consistent with that obtained from direct modelling of the Stokes V profiles. We derive a wind magnetic confinement parameter η* ≃ 100, leading to an Alfvén radius RA ≃ 3-5R*, and a Kepler radius RK ≃ 20R*. This supports a physical scenario in which the Hα emission and other line variability have their origin in an oblique, corotating 'dynamical magnetosphere' structure resulting from a magnetically channelled wind. Nevertheless, the details of the formation of spectral lines and their variability within this framework remain generally poorly understood.
Este documento tiene una corrección (ver documento relacionado).
Instituto de Astrofísica de La Plata
Materia
Ciencias Astronómicas
28° 2561
Stars: individual: CPD
Stars: magnetic field
Stars: massive
Stars: rotation
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:10915/86059

id SEDICI_e0739d72f24487fe111bad50efc7366d
oai_identifier_str oai:sedici.unlp.edu.ar:10915/86059
network_acronym_str SEDICI
repository_id_str 1329
network_name_str SEDICI (UNLP)
spelling Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561Wade, G. A.Barbá, Rodolfo HéctorGrunhut, J.Martins, F.Petit, V.Sundqvist, J. O.Townsend, R. H. D.Walborn, N. R.Alecian, E.Alfaro, E. J.Maíz Apellániz, J.Arias, Julia InésGamen, Roberto ClaudioMorrell, Nidia IreneNazé, Y.Sota, A.Doula, A. udMiMeS CollaborationCiencias Astronómicas28° 2561Stars: individual: CPDStars: magnetic fieldStars: massiveStars: rotationWe report magnetic and spectroscopic observations and modelling of the Of?p star CPD-28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and wind-sensitive spectral lines. A period search results in an unambiguous 73.41 d variability period. High-resolution spectropolarimetric data analysed using least-squares deconvolution yield a Zeeman signature detected in the mean Stokes V profile corresponding to phase 0.5 of the spectral ephemeris. Interpreting the 73.41 d period as the stellar rotational period, we have phased the equivalent widths and inferred longitudinal field measurements. The phased magnetic data exhibit a weak sinusoidal variation, with maximum of about 565 G at phase 0.5, and a minimum of about -335 G at phase 0.0, with extrema approximately in phase with the (double-wave) Hα equivalent width variation. Modelling of the Hα equivalent width variation assuming a quasi-3D magnetospheric model produces a unique solution for the ambiguous couplet of inclination and magnetic obliquity angles: (i, β) or (β, i) = (35°, 90°). Adopting either geometry, the longitudinal field variation yields a dipole polar intensity B<sub>d</sub> = 2.6 ± 0.9 kG, consistent with that obtained from direct modelling of the Stokes V profiles. We derive a wind magnetic confinement parameter η<sub>*</sub> ≃ 100, leading to an Alfvén radius R<sub>A</sub> ≃ 3-5R<sub>*</sub>, and a Kepler radius R<sub>K</sub> ≃ 20R<sub>*</sub>. This supports a physical scenario in which the Hα emission and other line variability have their origin in an oblique, corotating 'dynamical magnetosphere' structure resulting from a magnetically channelled wind. Nevertheless, the details of the formation of spectral lines and their variability within this framework remain generally poorly understood.Este documento tiene una corrección (ver documento relacionado).Instituto de Astrofísica de La Plata2015info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionArticulohttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdf2551-2567http://sedici.unlp.edu.ar/handle/10915/86059enginfo:eu-repo/semantics/altIdentifier/issn/0035-8711info:eu-repo/semantics/altIdentifier/doi/10.1093/mnras/stu2548info:eu-repo/semantics/reference/hdl/10915/87057info: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:UNLP2025-09-29T11:17:00Zoai:sedici.unlp.edu.ar:10915/86059Institucionalhttp://sedici.unlp.edu.ar/Universidad públicaNo correspondehttp://sedici.unlp.edu.ar/oai/snrdalira@sedici.unlp.edu.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:13292025-09-29 11:17:00.375SEDICI (UNLP) - Universidad Nacional de La Platafalse
dc.title.none.fl_str_mv Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
title Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
spellingShingle Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
Wade, G. A.
Ciencias Astronómicas
28° 2561
Stars: individual: CPD
Stars: magnetic field
Stars: massive
Stars: rotation
title_short Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
title_full Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
title_fullStr Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
title_full_unstemmed Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
title_sort Rotation, spectral variability, magnetic geometry and magnetosphere of the Of?p star CPD -28° 2561
dc.creator.none.fl_str_mv Wade, G. A.
Barbá, Rodolfo Héctor
Grunhut, J.
Martins, F.
Petit, V.
Sundqvist, J. O.
Townsend, R. H. D.
Walborn, N. R.
Alecian, E.
Alfaro, E. J.
Maíz Apellániz, J.
Arias, Julia Inés
Gamen, Roberto Claudio
Morrell, Nidia Irene
Nazé, Y.
Sota, A.
Doula, A. ud
MiMeS Collaboration
author Wade, G. A.
author_facet Wade, G. A.
Barbá, Rodolfo Héctor
Grunhut, J.
Martins, F.
Petit, V.
Sundqvist, J. O.
Townsend, R. H. D.
Walborn, N. R.
Alecian, E.
Alfaro, E. J.
Maíz Apellániz, J.
Arias, Julia Inés
Gamen, Roberto Claudio
Morrell, Nidia Irene
Nazé, Y.
Sota, A.
Doula, A. ud
MiMeS Collaboration
author_role author
author2 Barbá, Rodolfo Héctor
Grunhut, J.
Martins, F.
Petit, V.
Sundqvist, J. O.
Townsend, R. H. D.
Walborn, N. R.
Alecian, E.
Alfaro, E. J.
Maíz Apellániz, J.
Arias, Julia Inés
Gamen, Roberto Claudio
Morrell, Nidia Irene
Nazé, Y.
Sota, A.
Doula, A. ud
MiMeS Collaboration
author2_role author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv Ciencias Astronómicas
28° 2561
Stars: individual: CPD
Stars: magnetic field
Stars: massive
Stars: rotation
topic Ciencias Astronómicas
28° 2561
Stars: individual: CPD
Stars: magnetic field
Stars: massive
Stars: rotation
dc.description.none.fl_txt_mv We report magnetic and spectroscopic observations and modelling of the Of?p star CPD-28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and wind-sensitive spectral lines. A period search results in an unambiguous 73.41 d variability period. High-resolution spectropolarimetric data analysed using least-squares deconvolution yield a Zeeman signature detected in the mean Stokes V profile corresponding to phase 0.5 of the spectral ephemeris. Interpreting the 73.41 d period as the stellar rotational period, we have phased the equivalent widths and inferred longitudinal field measurements. The phased magnetic data exhibit a weak sinusoidal variation, with maximum of about 565 G at phase 0.5, and a minimum of about -335 G at phase 0.0, with extrema approximately in phase with the (double-wave) Hα equivalent width variation. Modelling of the Hα equivalent width variation assuming a quasi-3D magnetospheric model produces a unique solution for the ambiguous couplet of inclination and magnetic obliquity angles: (i, β) or (β, i) = (35°, 90°). Adopting either geometry, the longitudinal field variation yields a dipole polar intensity B<sub>d</sub> = 2.6 ± 0.9 kG, consistent with that obtained from direct modelling of the Stokes V profiles. We derive a wind magnetic confinement parameter η<sub>*</sub> ≃ 100, leading to an Alfvén radius R<sub>A</sub> ≃ 3-5R<sub>*</sub>, and a Kepler radius R<sub>K</sub> ≃ 20R<sub>*</sub>. This supports a physical scenario in which the Hα emission and other line variability have their origin in an oblique, corotating 'dynamical magnetosphere' structure resulting from a magnetically channelled wind. Nevertheless, the details of the formation of spectral lines and their variability within this framework remain generally poorly understood.
Este documento tiene una corrección (ver documento relacionado).
Instituto de Astrofísica de La Plata
description We report magnetic and spectroscopic observations and modelling of the Of?p star CPD-28° 2561. Using more than 75 new spectra, we have measured the equivalent width variations and examined the dynamic spectra of photospheric and wind-sensitive spectral lines. A period search results in an unambiguous 73.41 d variability period. High-resolution spectropolarimetric data analysed using least-squares deconvolution yield a Zeeman signature detected in the mean Stokes V profile corresponding to phase 0.5 of the spectral ephemeris. Interpreting the 73.41 d period as the stellar rotational period, we have phased the equivalent widths and inferred longitudinal field measurements. The phased magnetic data exhibit a weak sinusoidal variation, with maximum of about 565 G at phase 0.5, and a minimum of about -335 G at phase 0.0, with extrema approximately in phase with the (double-wave) Hα equivalent width variation. Modelling of the Hα equivalent width variation assuming a quasi-3D magnetospheric model produces a unique solution for the ambiguous couplet of inclination and magnetic obliquity angles: (i, β) or (β, i) = (35°, 90°). Adopting either geometry, the longitudinal field variation yields a dipole polar intensity B<sub>d</sub> = 2.6 ± 0.9 kG, consistent with that obtained from direct modelling of the Stokes V profiles. We derive a wind magnetic confinement parameter η<sub>*</sub> ≃ 100, leading to an Alfvén radius R<sub>A</sub> ≃ 3-5R<sub>*</sub>, and a Kepler radius R<sub>K</sub> ≃ 20R<sub>*</sub>. This supports a physical scenario in which the Hα emission and other line variability have their origin in an oblique, corotating 'dynamical magnetosphere' structure resulting from a magnetically channelled wind. Nevertheless, the details of the formation of spectral lines and their variability within this framework remain generally poorly understood.
publishDate 2015
dc.date.none.fl_str_mv 2015
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/10915/86059
url http://sedici.unlp.edu.ar/handle/10915/86059
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/issn/0035-8711
info:eu-repo/semantics/altIdentifier/doi/10.1093/mnras/stu2548
info:eu-repo/semantics/reference/hdl/10915/87057
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
2551-2567
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_ 1844616043029331968
score 13.070432