Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ?
We aim at a highly sensitive search for weak magnetic fields in main sequence stars of intermediate mass, by scanning classes of stars with no previously reported magnetic members. After detecting a weak magnetic field on the normal, rapidly rotating A-type star Vega, we concentrate here on the brig...
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ftdatacite:10.48550/arxiv.1106.5363 2023-05-15T18:50:48+02:00 Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? Petit, P. Lignières, F. Aurière, M. Wade, G. A. Alina, D. Ballot, J. Böhm, T. Jouve, L. Oza, A. Paletou, F. Théado, S. 2011 https://dx.doi.org/10.48550/arxiv.1106.5363 https://arxiv.org/abs/1106.5363 unknown arXiv https://dx.doi.org/10.1051/0004-6361/201117573 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 2011 ftdatacite https://doi.org/10.48550/arxiv.1106.5363 https://doi.org/10.1051/0004-6361/201117573 2022-04-01T14:22:41Z We aim at a highly sensitive search for weak magnetic fields in main sequence stars of intermediate mass, by scanning classes of stars with no previously reported magnetic members. After detecting a weak magnetic field on the normal, rapidly rotating A-type star Vega, we concentrate here on the bright star Sirius A, taken as a prototypical, chemically peculiar, moderately rotating Am star. We employed the NARVAL and ESPaDOnS high-resolution spectropolarimeters to collect 442 circularly polarized spectra, complemented by 60 linearly polarized spectra. Using a list of about 1,100 photospheric spectral lines, we computed a cross correlation line profile from every spectrum, leading to a signal-to-noise ratio of up to 30,000 in the polarized profile. We report the repeated detection of circularly polarized, highly asymmetric signatures in the line profiles, interpreted as Zeeman signatures of a large-scale photospheric magnetic field, with a line-of-sight component equal to $0.2 \pm 0.1$ G. This is the first polarimetric detection of a surface magnetic field on an Am star. Using rough estimates of the physical properties of the upper layers of Sirius A, we suggest that a dynamo operating in the shallow convective envelope cannot account for the field strength reported here. Together with the magnetic field of Vega, this result confirms that a new class of magnetic objects exists among non Ap/Bp intermediate-mass stars, and it may indicate that a significant fraction of tepid stars are magnetic. : Accepted by Astronomy and Astrophysics Text narval narval DataCite Metadata Store (German National Library of Science and Technology) Sirius ENVELOPE(163.250,163.250,-84.133,-84.133) |
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DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
unknown |
topic |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
spellingShingle |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences Petit, P. Lignières, F. Aurière, M. Wade, G. A. Alina, D. Ballot, J. Böhm, T. Jouve, L. Oza, A. Paletou, F. Théado, S. Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
topic_facet |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
description |
We aim at a highly sensitive search for weak magnetic fields in main sequence stars of intermediate mass, by scanning classes of stars with no previously reported magnetic members. After detecting a weak magnetic field on the normal, rapidly rotating A-type star Vega, we concentrate here on the bright star Sirius A, taken as a prototypical, chemically peculiar, moderately rotating Am star. We employed the NARVAL and ESPaDOnS high-resolution spectropolarimeters to collect 442 circularly polarized spectra, complemented by 60 linearly polarized spectra. Using a list of about 1,100 photospheric spectral lines, we computed a cross correlation line profile from every spectrum, leading to a signal-to-noise ratio of up to 30,000 in the polarized profile. We report the repeated detection of circularly polarized, highly asymmetric signatures in the line profiles, interpreted as Zeeman signatures of a large-scale photospheric magnetic field, with a line-of-sight component equal to $0.2 \pm 0.1$ G. This is the first polarimetric detection of a surface magnetic field on an Am star. Using rough estimates of the physical properties of the upper layers of Sirius A, we suggest that a dynamo operating in the shallow convective envelope cannot account for the field strength reported here. Together with the magnetic field of Vega, this result confirms that a new class of magnetic objects exists among non Ap/Bp intermediate-mass stars, and it may indicate that a significant fraction of tepid stars are magnetic. : Accepted by Astronomy and Astrophysics |
format |
Text |
author |
Petit, P. Lignières, F. Aurière, M. Wade, G. A. Alina, D. Ballot, J. Böhm, T. Jouve, L. Oza, A. Paletou, F. Théado, S. |
author_facet |
Petit, P. Lignières, F. Aurière, M. Wade, G. A. Alina, D. Ballot, J. Böhm, T. Jouve, L. Oza, A. Paletou, F. Théado, S. |
author_sort |
Petit, P. |
title |
Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
title_short |
Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
title_full |
Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
title_fullStr |
Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
title_full_unstemmed |
Detection of a weak surface magnetic field on Sirius A: are all tepid stars magnetic ? |
title_sort |
detection of a weak surface magnetic field on sirius a: are all tepid stars magnetic ? |
publisher |
arXiv |
publishDate |
2011 |
url |
https://dx.doi.org/10.48550/arxiv.1106.5363 https://arxiv.org/abs/1106.5363 |
long_lat |
ENVELOPE(163.250,163.250,-84.133,-84.133) |
geographic |
Sirius |
geographic_facet |
Sirius |
genre |
narval narval |
genre_facet |
narval narval |
op_relation |
https://dx.doi.org/10.1051/0004-6361/201117573 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1106.5363 https://doi.org/10.1051/0004-6361/201117573 |
_version_ |
1766244557733756928 |