EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars
International audience Aims. We observe the slowly-rotating, active, single giant, EK Eri, to study and infer the nature of its magnetic field directly. Methods: We used the spectropolarimeter NARVAL at the Telescope Bernard Lyot, Pic du Midi Observatory, and the Least Square Deconvolution method to...
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ftccsdartic:oai:HAL:hal-00392053v1 2023-05-15T18:50:44+02:00 EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars Aurière, M. Konstantinova-Antova, R. Petit, P. Charbonnel, C. Dintrans, B. Lignières, F. Roudier, T. Alecian, E. Donati, J. F. Landstreet, J. D. Wade, G. A. Laboratoire Astrophysique de Toulouse-Tarbes (LATT) Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Observatoire Astronomique de l'Université de Genève (ObsGE) Université de Genève (UNIGE) University of Western Ontario (UWO) 2008-11 https://hal.archives-ouvertes.fr/hal-00392053 https://doi.org/10.1051/0004-6361:200810502 en eng HAL CCSD EDP Sciences info:eu-repo/semantics/altIdentifier/arxiv/0810.2228 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:200810502 hal-00392053 https://hal.archives-ouvertes.fr/hal-00392053 ARXIV: 0810.2228 BIBCODE: 2008A&A.491.499A doi:10.1051/0004-6361:200810502 ISSN: 0004-6361 EISSN: 1432-0756 Astronomy and Astrophysics - A&A https://hal.archives-ouvertes.fr/hal-00392053 Astronomy and Astrophysics - A&A, EDP Sciences, 2008, 491, pp.499-505. ⟨10.1051/0004-6361:200810502⟩ stars: individual: EK Eridani stars: magnetic fields stars: late-type [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] info:eu-repo/semantics/article Journal articles 2008 ftccsdartic https://doi.org/10.1051/0004-6361:200810502 2021-11-21T04:56:59Z International audience Aims. We observe the slowly-rotating, active, single giant, EK Eri, to study and infer the nature of its magnetic field directly. Methods: We used the spectropolarimeter NARVAL at the Telescope Bernard Lyot, Pic du Midi Observatory, and the Least Square Deconvolution method to create high signal-to-noise ratio Stokes V profiles. We fitted the Stokes V profiles with a model of the large-scale magnetic field. We studied the classical activity indicators, the Ca ii H and K lines, the Ca ii infrared triplet, and Hα line. Results: We detected the Stokes V signal of EK Eri securely and measured the longitudinal magnetic field Bl for seven individual dates spanning 60% of the rotational period. The measured longitudinal magnetic field of EK Eri reached about 100 G and was as strong as fields observed in RSCVn or FK Com type stars: this was found to be extraordinary when compared with the weak fields observed at the surfaces of slowly-rotating MS stars or any single red giant previously observed with NARVAL. From our modeling, we infer that the mean surface magnetic field is about 270 G, and that the large scale magnetic field is dominated by a poloidal component. This is compatible with expectations for the descendant of a strongly magnetic Ap star. Based on data obtained using the Télescope Bernard Lyot at Observatoire du Pic du Midi, CNRS/INSU and Université de Toulouse, France. Article in Journal/Newspaper narval narval Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
stars: individual: EK Eridani stars: magnetic fields stars: late-type [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] |
spellingShingle |
stars: individual: EK Eridani stars: magnetic fields stars: late-type [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] Aurière, M. Konstantinova-Antova, R. Petit, P. Charbonnel, C. Dintrans, B. Lignières, F. Roudier, T. Alecian, E. Donati, J. F. Landstreet, J. D. Wade, G. A. EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
topic_facet |
stars: individual: EK Eridani stars: magnetic fields stars: late-type [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] |
description |
International audience Aims. We observe the slowly-rotating, active, single giant, EK Eri, to study and infer the nature of its magnetic field directly. Methods: We used the spectropolarimeter NARVAL at the Telescope Bernard Lyot, Pic du Midi Observatory, and the Least Square Deconvolution method to create high signal-to-noise ratio Stokes V profiles. We fitted the Stokes V profiles with a model of the large-scale magnetic field. We studied the classical activity indicators, the Ca ii H and K lines, the Ca ii infrared triplet, and Hα line. Results: We detected the Stokes V signal of EK Eri securely and measured the longitudinal magnetic field Bl for seven individual dates spanning 60% of the rotational period. The measured longitudinal magnetic field of EK Eri reached about 100 G and was as strong as fields observed in RSCVn or FK Com type stars: this was found to be extraordinary when compared with the weak fields observed at the surfaces of slowly-rotating MS stars or any single red giant previously observed with NARVAL. From our modeling, we infer that the mean surface magnetic field is about 270 G, and that the large scale magnetic field is dominated by a poloidal component. This is compatible with expectations for the descendant of a strongly magnetic Ap star. Based on data obtained using the Télescope Bernard Lyot at Observatoire du Pic du Midi, CNRS/INSU and Université de Toulouse, France. |
author2 |
Laboratoire Astrophysique de Toulouse-Tarbes (LATT) Université Toulouse III - Paul Sabatier (UT3) Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP) Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS) Observatoire Astronomique de l'Université de Genève (ObsGE) Université de Genève (UNIGE) University of Western Ontario (UWO) |
format |
Article in Journal/Newspaper |
author |
Aurière, M. Konstantinova-Antova, R. Petit, P. Charbonnel, C. Dintrans, B. Lignières, F. Roudier, T. Alecian, E. Donati, J. F. Landstreet, J. D. Wade, G. A. |
author_facet |
Aurière, M. Konstantinova-Antova, R. Petit, P. Charbonnel, C. Dintrans, B. Lignières, F. Roudier, T. Alecian, E. Donati, J. F. Landstreet, J. D. Wade, G. A. |
author_sort |
Aurière, M. |
title |
EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
title_short |
EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
title_full |
EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
title_fullStr |
EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
title_full_unstemmed |
EK Eridani: the tip of the iceberg of giants which have evolved from magnetic Ap stars |
title_sort |
ek eridani: the tip of the iceberg of giants which have evolved from magnetic ap stars |
publisher |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.archives-ouvertes.fr/hal-00392053 https://doi.org/10.1051/0004-6361:200810502 |
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-00392053 Astronomy and Astrophysics - A&A, EDP Sciences, 2008, 491, pp.499-505. ⟨10.1051/0004-6361:200810502⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/0810.2228 info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361:200810502 hal-00392053 https://hal.archives-ouvertes.fr/hal-00392053 ARXIV: 0810.2228 BIBCODE: 2008A&A.491.499A doi:10.1051/0004-6361:200810502 |
op_doi |
https://doi.org/10.1051/0004-6361:200810502 |
_version_ |
1766244487616528384 |