The magnetic fields at the surface of active single G-K giants
International audience We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. We use the spectropolarimeters Narval and ESPaDOnS to detect circular polarization within the photospheric absorption li...
Published in: | Astronomy & Astrophysics |
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Main Authors: | , , , , , , , , , , , , , , , , , |
Other Authors: | , , , , , , , , , , , , , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2015
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Subjects: | |
Online Access: | https://hal.in2p3.fr/in2p3-01954376 https://doi.org/10.1051/0004-6361/201424579 |
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HAL-IN2P3 (Institut national de physique nucléaire et de physique des particules) |
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English |
topic |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
spellingShingle |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] Auriere, M. Konstantinova-Antova, R. Charbonnel, Corinne Wade, G. Tsvetkova, S. Petit, P. Dintrans, B. Drake, N. Decressin, T. Lagarde, N. Donati, J.-F. Roudier, T. Lignieres, F. Schröder, P. Landstreet, J. Lèbre, A. Weiss, W. Zahn, J.-P. The magnetic fields at the surface of active single G-K giants |
topic_facet |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
description |
International audience We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. We use the spectropolarimeters Narval and ESPaDOnS to detect circular polarization within the photospheric absorption lines of our targets and use the least-squares deconvolution (LSD) method. We also measure the classical S-index activity indicator, and the stellar radial velocity. To infer the evolutionary status of our giants and to interpret our results, we use state-of-the-art stellar evolutionary models with predictions of convective turnover times. We unambiguously detect magnetic fields via Zeeman signatures in 29 of the 48 red giants in our sample. Zeeman signatures are found in all but one of the 24 red giants exhibiting signs of activity, as well as 6 out of 17 bright giant stars.The majority of the magnetically detected giants are either in the first dredge up phase or at the beginning of core He burning, i.e. phases when the convective turnover time is at a maximum: this corresponds to a 'magnetic strip' for red giants in the Hertzsprung-Russell diagram. A close study of the 16 giants with known rotational periods shows that the measured magnetic field strength is tightly correlated with the rotational properties, namely to the rotational period and to the Rossby number Ro. Our results show that the magnetic fields of these giants are produced by a dynamo. Four stars for which the magnetic field is measured to be outstandingly strong with respect to that expected from the rotational period/magnetic field relation or their evolutionary status are interpreted as being probable descendants of magnetic Ap stars. In addition to the weak-field giant Pollux, 4 bright giants (Aldebaran, Alphard, Arcturus, eta Psc) are detected with magnetic field strength at the sub-gauss level. |
author2 |
Institut de recherche en astrophysique et planétologie (IRAP) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Bulgarian Academy of Sciences (BAS) Observatoire Astronomique de l'Université de Genève (ObsGE) Université de Genève = University of Geneva (UNIGE) Royal Military College of Canada (RMCC) Royal Military College of Canada Sobolev Astronomical Institute Saint-Petersburg State University of Aerospace Instrumentation (SUAI) Observatorio Nacional Rio de Janeiro INAF - Osservatorio Astronomico di Roma (OAR) Istituto Nazionale di Astrofisica (INAF) School of Physics and Astronomy Birmingham University of Birmingham Birmingham Universidad de Guanajuato Armagh Observatory Armagh Laboratoire Univers et Particules de Montpellier (LUPM) Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Laboratoire Univers et Théories (LUTH (UMR_8102)) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Auriere, M. Konstantinova-Antova, R. Charbonnel, Corinne Wade, G. Tsvetkova, S. Petit, P. Dintrans, B. Drake, N. Decressin, T. Lagarde, N. Donati, J.-F. Roudier, T. Lignieres, F. Schröder, P. Landstreet, J. Lèbre, A. Weiss, W. Zahn, J.-P. |
author_facet |
Auriere, M. Konstantinova-Antova, R. Charbonnel, Corinne Wade, G. Tsvetkova, S. Petit, P. Dintrans, B. Drake, N. Decressin, T. Lagarde, N. Donati, J.-F. Roudier, T. Lignieres, F. Schröder, P. Landstreet, J. Lèbre, A. Weiss, W. Zahn, J.-P. |
author_sort |
Auriere, M. |
title |
The magnetic fields at the surface of active single G-K giants |
title_short |
The magnetic fields at the surface of active single G-K giants |
title_full |
The magnetic fields at the surface of active single G-K giants |
title_fullStr |
The magnetic fields at the surface of active single G-K giants |
title_full_unstemmed |
The magnetic fields at the surface of active single G-K giants |
title_sort |
magnetic fields at the surface of active single g-k giants |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://hal.in2p3.fr/in2p3-01954376 https://doi.org/10.1051/0004-6361/201424579 |
long_lat |
ENVELOPE(-62.917,-62.917,-64.300,-64.300) ENVELOPE(140.018,140.018,-66.660,-66.660) |
geographic |
Eta Pollux |
geographic_facet |
Eta Pollux |
genre |
narval narval |
genre_facet |
narval narval |
op_source |
ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.in2p3.fr/in2p3-01954376 Astronomy and Astrophysics - A&A, 2015, 574, pp.A90. ⟨10.1051/0004-6361/201424579⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/1411.6230 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201424579 in2p3-01954376 https://hal.in2p3.fr/in2p3-01954376 ARXIV: 1411.6230 BIBCODE: 2015A&A.574A.90A doi:10.1051/0004-6361/201424579 |
op_doi |
https://doi.org/10.1051/0004-6361/201424579 |
container_title |
Astronomy & Astrophysics |
container_volume |
574 |
container_start_page |
A90 |
_version_ |
1809816234458349568 |
spelling |
fthalin2p3:oai:HAL:in2p3-01954376v1 2024-09-09T20:14:34+00:00 The magnetic fields at the surface of active single G-K giants Auriere, M. Konstantinova-Antova, R. Charbonnel, Corinne Wade, G. Tsvetkova, S. Petit, P. Dintrans, B. Drake, N. Decressin, T. Lagarde, N. Donati, J.-F. Roudier, T. Lignieres, F. Schröder, P. Landstreet, J. Lèbre, A. Weiss, W. Zahn, J.-P. Institut de recherche en astrophysique et planétologie (IRAP) Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3) Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS) Bulgarian Academy of Sciences (BAS) Observatoire Astronomique de l'Université de Genève (ObsGE) Université de Genève = University of Geneva (UNIGE) Royal Military College of Canada (RMCC) Royal Military College of Canada Sobolev Astronomical Institute Saint-Petersburg State University of Aerospace Instrumentation (SUAI) Observatorio Nacional Rio de Janeiro INAF - Osservatorio Astronomico di Roma (OAR) Istituto Nazionale di Astrofisica (INAF) School of Physics and Astronomy Birmingham University of Birmingham Birmingham Universidad de Guanajuato Armagh Observatory Armagh Laboratoire Univers et Particules de Montpellier (LUPM) Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS) Laboratoire Univers et Théories (LUTH (UMR_8102)) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS) 2015-02 https://hal.in2p3.fr/in2p3-01954376 https://doi.org/10.1051/0004-6361/201424579 en eng HAL CCSD EDP Sciences info:eu-repo/semantics/altIdentifier/arxiv/1411.6230 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201424579 in2p3-01954376 https://hal.in2p3.fr/in2p3-01954376 ARXIV: 1411.6230 BIBCODE: 2015A&A.574A.90A doi:10.1051/0004-6361/201424579 ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.in2p3.fr/in2p3-01954376 Astronomy and Astrophysics - A&A, 2015, 574, pp.A90. ⟨10.1051/0004-6361/201424579⟩ [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 2015 fthalin2p3 https://doi.org/10.1051/0004-6361/201424579 2024-06-25T23:58:10Z International audience We investigate the magnetic field at the surface of 48 red giants selected as promising for detection of Stokes V Zeeman signatures in their spectral lines. We use the spectropolarimeters Narval and ESPaDOnS to detect circular polarization within the photospheric absorption lines of our targets and use the least-squares deconvolution (LSD) method. We also measure the classical S-index activity indicator, and the stellar radial velocity. To infer the evolutionary status of our giants and to interpret our results, we use state-of-the-art stellar evolutionary models with predictions of convective turnover times. We unambiguously detect magnetic fields via Zeeman signatures in 29 of the 48 red giants in our sample. Zeeman signatures are found in all but one of the 24 red giants exhibiting signs of activity, as well as 6 out of 17 bright giant stars.The majority of the magnetically detected giants are either in the first dredge up phase or at the beginning of core He burning, i.e. phases when the convective turnover time is at a maximum: this corresponds to a 'magnetic strip' for red giants in the Hertzsprung-Russell diagram. A close study of the 16 giants with known rotational periods shows that the measured magnetic field strength is tightly correlated with the rotational properties, namely to the rotational period and to the Rossby number Ro. Our results show that the magnetic fields of these giants are produced by a dynamo. Four stars for which the magnetic field is measured to be outstandingly strong with respect to that expected from the rotational period/magnetic field relation or their evolutionary status are interpreted as being probable descendants of magnetic Ap stars. In addition to the weak-field giant Pollux, 4 bright giants (Aldebaran, Alphard, Arcturus, eta Psc) are detected with magnetic field strength at the sub-gauss level. Article in Journal/Newspaper narval narval HAL-IN2P3 (Institut national de physique nucléaire et de physique des particules) Eta ENVELOPE(-62.917,-62.917,-64.300,-64.300) Pollux ENVELOPE(140.018,140.018,-66.660,-66.660) Astronomy & Astrophysics 574 A90 |