The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae
Context: When crossing the Hertzsprung gap, intermediate-mass stars develop a convective envelope. Fast rotators on the main sequence, or Ap star descendants, are expected to become magnetic active subgiants during this evolutionary phase. Aims: We compare the surface magnetic fields and activity in...
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ftdatacite:10.48550/arxiv.1604.07647 2023-05-15T18:50:51+02:00 The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae Borisova, A. Aurière, M. Petit, P. Konstantinova-Antova, R. Charbonnel, C. Drake, N. A. 2016 https://dx.doi.org/10.48550/arxiv.1604.07647 https://arxiv.org/abs/1604.07647 unknown arXiv https://dx.doi.org/10.1051/0004-6361/201526726 arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences article-journal Article ScholarlyArticle Text 2016 ftdatacite https://doi.org/10.48550/arxiv.1604.07647 https://doi.org/10.1051/0004-6361/201526726 2022-04-01T11:40:58Z Context: When crossing the Hertzsprung gap, intermediate-mass stars develop a convective envelope. Fast rotators on the main sequence, or Ap star descendants, are expected to become magnetic active subgiants during this evolutionary phase. Aims: We compare the surface magnetic fields and activity indicators of two active, fast rotating red giants with similar masses and spectral class but diferent rotation rates - OU And (Prot=24.2 d) and 31 Com (Prot=6.8 d) - to address the question of the origin of their magnetism and high activity. Methods: Observations were carried out with the Narval spectropolarimeter in 2008 and 2013.We used the least squares deconvolution technique to extract Stokes V and I profiles to detect Zeeman signatures of the magnetic field of the stars. We provide Zeeman-Doppler imaging, activity indicator monitoring, and a precise estimation of stellar parameters. We use stellar evolutionary models to infer the evolutionary status and the initial rotation velocity on the main sequence. Results: The detected magnetic field of OU And is a strong one. Its longitudinal component Bl reaches 40 G and presents an about sinusoidal variation with reversal of the polarity. The magnetic topology of OU And is dominated by large scale elements and is mainly poloidal with an important dipole component, and a significant toroidal component. The detected magnetic field of 31 Com is weaker, with a magnetic map showing a more complex field geometry, and poloidal and toroidal components of equal contributions. The evolutionary models show that the progenitors of OU And and 31 Com must have been rotat Conclusions: OU And appears to be the probable descendant of a magnetic Ap star, and 31 Com the descendant of a relatively fast rotator on the main sequence. : 16 pages, 12 figures Text narval narval DataCite Metadata Store (German National Library of Science and Technology) |
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Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
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Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences Borisova, A. Aurière, M. Petit, P. Konstantinova-Antova, R. Charbonnel, C. Drake, N. A. The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
topic_facet |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
description |
Context: When crossing the Hertzsprung gap, intermediate-mass stars develop a convective envelope. Fast rotators on the main sequence, or Ap star descendants, are expected to become magnetic active subgiants during this evolutionary phase. Aims: We compare the surface magnetic fields and activity indicators of two active, fast rotating red giants with similar masses and spectral class but diferent rotation rates - OU And (Prot=24.2 d) and 31 Com (Prot=6.8 d) - to address the question of the origin of their magnetism and high activity. Methods: Observations were carried out with the Narval spectropolarimeter in 2008 and 2013.We used the least squares deconvolution technique to extract Stokes V and I profiles to detect Zeeman signatures of the magnetic field of the stars. We provide Zeeman-Doppler imaging, activity indicator monitoring, and a precise estimation of stellar parameters. We use stellar evolutionary models to infer the evolutionary status and the initial rotation velocity on the main sequence. Results: The detected magnetic field of OU And is a strong one. Its longitudinal component Bl reaches 40 G and presents an about sinusoidal variation with reversal of the polarity. The magnetic topology of OU And is dominated by large scale elements and is mainly poloidal with an important dipole component, and a significant toroidal component. The detected magnetic field of 31 Com is weaker, with a magnetic map showing a more complex field geometry, and poloidal and toroidal components of equal contributions. The evolutionary models show that the progenitors of OU And and 31 Com must have been rotat Conclusions: OU And appears to be the probable descendant of a magnetic Ap star, and 31 Com the descendant of a relatively fast rotator on the main sequence. : 16 pages, 12 figures |
format |
Text |
author |
Borisova, A. Aurière, M. Petit, P. Konstantinova-Antova, R. Charbonnel, C. Drake, N. A. |
author_facet |
Borisova, A. Aurière, M. Petit, P. Konstantinova-Antova, R. Charbonnel, C. Drake, N. A. |
author_sort |
Borisova, A. |
title |
The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
title_short |
The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
title_full |
The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
title_fullStr |
The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
title_full_unstemmed |
The different origins of magnetic fields and activity in the Hertzsprung gap stars, OU Andromedae and 31 Comae |
title_sort |
different origins of magnetic fields and activity in the hertzsprung gap stars, ou andromedae and 31 comae |
publisher |
arXiv |
publishDate |
2016 |
url |
https://dx.doi.org/10.48550/arxiv.1604.07647 https://arxiv.org/abs/1604.07647 |
genre |
narval narval |
genre_facet |
narval narval |
op_relation |
https://dx.doi.org/10.1051/0004-6361/201526726 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1604.07647 https://doi.org/10.1051/0004-6361/201526726 |
_version_ |
1766244605556162560 |