Shock-induced polarized hydrogen emission lines in the Mira star o Ceti
International audience Context. In the spectra of variable pulsating stars, especially Mira stars, the detection of intense hydrogen emission lines has been explained by the presence of a radiative and hypersonic shock wave, periodically propagating throughout the stellar atmosphere. Previous observ...
Published in: | Astronomy & Astrophysics |
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Main Authors: | , , |
Other Authors: | , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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HAL CCSD
2011
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Online Access: | https://hal.archives-ouvertes.fr/hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312/document https://hal.archives-ouvertes.fr/hal-00644312/file/aa17748-11.pdf https://doi.org/10.1051/0004-6361/201117748 |
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Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
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language |
English |
topic |
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
spellingShingle |
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] FABAS, Nicolas LEBRE, Agnès Gillet, Denis Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
topic_facet |
[PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
description |
International audience Context. In the spectra of variable pulsating stars, especially Mira stars, the detection of intense hydrogen emission lines has been explained by the presence of a radiative and hypersonic shock wave, periodically propagating throughout the stellar atmosphere. Previous observation of the Mira star o Ceti around one of its brightest maximum light led to the detection of a strong level of linear polarization associated to Balmer emissions, although the origin of this phenomenon is not fully explained yet. Aims: With the help of spectropolarimetry, we propose to investigate the nature of shock waves propagating throughout the stellar atmosphere and present, for o Ceti (the prototype of Mira stars), a full observational study of hydrogen emission lines formed in the radiative region of such a shock. Methods: Using the instrument NARVAL mounted on the Télescope Bernard Lyot (TBL) in Pic du Midi Observatory (France), we performed a spectropolarimetric monitoring of o Ceti during three consecutive pulsation cycles. For this survey, the four Stokes parameters (I for intensity, Q and U for linear polarization, and V for circular polarization) were systematically collected, with a particular emphasis on the maxima of luminosity, i.e. when a radiative shock wave is supposed to emerge from the photosphere and starts to propagate outward. Results: On hydrogen Balmer lines, over a large part of the luminosity cycle, we report clear detection of polarimetric structures in Q and U Stokes spectra (and also in V Stokes spectra but to a lesser extent). We report a temporal evolution of these spectropolarimetric signatures, which appear strongly correlated to the presence of an intense shock wave responsible for the hydrogen emission lines. We establish that the hydrogen lines are polarized by a physical process inherent to the mechanism responsible for the emission line formation: the shock wave itself. Two mechanisms are thus considered: a global one that implies a polarization induced by some giant ... |
author2 |
Astrophysique Stellaire Laboratoire Univers et Particules de Montpellier (LUPM) Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Observatoire de Haute-Provence (OHP) Institut Pythéas (OSU PYTHEAS) Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD) |
format |
Article in Journal/Newspaper |
author |
FABAS, Nicolas LEBRE, Agnès Gillet, Denis |
author_facet |
FABAS, Nicolas LEBRE, Agnès Gillet, Denis |
author_sort |
FABAS, Nicolas |
title |
Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
title_short |
Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
title_full |
Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
title_fullStr |
Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
title_full_unstemmed |
Shock-induced polarized hydrogen emission lines in the Mira star o Ceti |
title_sort |
shock-induced polarized hydrogen emission lines in the mira star o ceti |
publisher |
HAL CCSD |
publishDate |
2011 |
url |
https://hal.archives-ouvertes.fr/hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312/document https://hal.archives-ouvertes.fr/hal-00644312/file/aa17748-11.pdf https://doi.org/10.1051/0004-6361/201117748 |
long_lat |
ENVELOPE(10.500,10.500,-70.417,-70.417) |
geographic |
Mira |
geographic_facet |
Mira |
genre |
narval narval |
genre_facet |
narval narval |
op_source |
ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.archives-ouvertes.fr/hal-00644312 Astronomy and Astrophysics - A&A, EDP Sciences, 2011, 535, pp.A12. ⟨10.1051/0004-6361/201117748⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201117748 hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312/document https://hal.archives-ouvertes.fr/hal-00644312/file/aa17748-11.pdf BIBCODE: 2011A%26A.535A.12F doi:10.1051/0004-6361/201117748 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1051/0004-6361/201117748 |
container_title |
Astronomy & Astrophysics |
container_volume |
535 |
container_start_page |
A12 |
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1766244623652487168 |
spelling |
ftccsdartic:oai:HAL:hal-00644312v1 2023-05-15T18:50:52+02:00 Shock-induced polarized hydrogen emission lines in the Mira star o Ceti FABAS, Nicolas LEBRE, Agnès Gillet, Denis Astrophysique Stellaire Laboratoire Univers et Particules de Montpellier (LUPM) Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Observatoire de Haute-Provence (OHP) Institut Pythéas (OSU PYTHEAS) Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD) 2011-11-01 https://hal.archives-ouvertes.fr/hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312/document https://hal.archives-ouvertes.fr/hal-00644312/file/aa17748-11.pdf https://doi.org/10.1051/0004-6361/201117748 en eng HAL CCSD EDP Sciences info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201117748 hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312 https://hal.archives-ouvertes.fr/hal-00644312/document https://hal.archives-ouvertes.fr/hal-00644312/file/aa17748-11.pdf BIBCODE: 2011A%26A.535A.12F doi:10.1051/0004-6361/201117748 info:eu-repo/semantics/OpenAccess ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.archives-ouvertes.fr/hal-00644312 Astronomy and Astrophysics - A&A, EDP Sciences, 2011, 535, pp.A12. ⟨10.1051/0004-6361/201117748⟩ [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] info:eu-repo/semantics/article Journal articles 2011 ftccsdartic https://doi.org/10.1051/0004-6361/201117748 2021-10-24T17:09:53Z International audience Context. In the spectra of variable pulsating stars, especially Mira stars, the detection of intense hydrogen emission lines has been explained by the presence of a radiative and hypersonic shock wave, periodically propagating throughout the stellar atmosphere. Previous observation of the Mira star o Ceti around one of its brightest maximum light led to the detection of a strong level of linear polarization associated to Balmer emissions, although the origin of this phenomenon is not fully explained yet. Aims: With the help of spectropolarimetry, we propose to investigate the nature of shock waves propagating throughout the stellar atmosphere and present, for o Ceti (the prototype of Mira stars), a full observational study of hydrogen emission lines formed in the radiative region of such a shock. Methods: Using the instrument NARVAL mounted on the Télescope Bernard Lyot (TBL) in Pic du Midi Observatory (France), we performed a spectropolarimetric monitoring of o Ceti during three consecutive pulsation cycles. For this survey, the four Stokes parameters (I for intensity, Q and U for linear polarization, and V for circular polarization) were systematically collected, with a particular emphasis on the maxima of luminosity, i.e. when a radiative shock wave is supposed to emerge from the photosphere and starts to propagate outward. Results: On hydrogen Balmer lines, over a large part of the luminosity cycle, we report clear detection of polarimetric structures in Q and U Stokes spectra (and also in V Stokes spectra but to a lesser extent). We report a temporal evolution of these spectropolarimetric signatures, which appear strongly correlated to the presence of an intense shock wave responsible for the hydrogen emission lines. We establish that the hydrogen lines are polarized by a physical process inherent to the mechanism responsible for the emission line formation: the shock wave itself. Two mechanisms are thus considered: a global one that implies a polarization induced by some giant ... Article in Journal/Newspaper narval narval Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Mira ENVELOPE(10.500,10.500,-70.417,-70.417) Astronomy & Astrophysics 535 A12 |