gamma Peg: testing Vega-like magnetic fields in B stars
gam Peg is a bright B pulsator showing both p and g modes of beta Cep and SPB types. It has also been claimed to be a magnetic star by some authors while others do not detect a magnetic field. We aimed at checking for the presence of a field, characterise it if it exists or provide a firm upper limi...
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ftdatacite:10.48550/arxiv.1312.3521 2023-05-15T18:50:43+02:00 gamma Peg: testing Vega-like magnetic fields in B stars Neiner, C. Monin, D. Leroy, B. Mathis, S. Bohlender, D. 2013 https://dx.doi.org/10.48550/arxiv.1312.3521 https://arxiv.org/abs/1312.3521 unknown arXiv https://dx.doi.org/10.1051/0004-6361/201323093 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 2013 ftdatacite https://doi.org/10.48550/arxiv.1312.3521 https://doi.org/10.1051/0004-6361/201323093 2022-04-01T13:01:04Z gam Peg is a bright B pulsator showing both p and g modes of beta Cep and SPB types. It has also been claimed to be a magnetic star by some authors while others do not detect a magnetic field. We aimed at checking for the presence of a field, characterise it if it exists or provide a firm upper limit of its strength if it is not detected. If gam Peg is magnetic, it would make an ideal asteroseismic target to test various theoretical scenarios. If it is very weakly magnetic, it would be the first observation of an extension of Vega-like fields to early B stars. Finally, if it is not magnetic and we can provide a very low upper limit on its non-detected field, it would make an important result for stellar evolution models. We acquired high resolution, high signal-to-noise spectropolarimetric Narval data at TBL. We also gathered existing dimaPol@DAO and Musicos@TBL spectropolarimetric data. We analysed the Narval and Musicos observations using the LSD technique to derive the longitudinal magnetic field and Zeeman signatures in lines. The longitudinal field strength was also extracted from the Hbeta line observed with the DAO. With a Monte Carlo simulation we derived the maximum strength of the field possibly hosted by gam Peg. We find that no magnetic signatures are visible in the very high quality spectropolarimetric data. The average longitudinal field measured in the Narval data is Bl=-0.1+/-0.4 G. We derive a very strict upper limit of the dipolar field strength of Bpol~40 G. We conclude that gamma Peg is not magnetic: it does not host a strong stable fossil field as observed in a fraction of massive stars, nor a very weak Vega-like field. There is therefore no evidence that Vega-like fields exist in B stars contrary to the predictions by fossil field dichotomy scenarios. These scenarios should thus be revised. Our results also provide strong constraints for stellar evolution models. : 8 pages, accepted in A&A Text narval narval DataCite Metadata Store (German National Library of Science and Technology) Gam ENVELOPE(-57.955,-57.955,-61.923,-61.923) |
institution |
Open Polar |
collection |
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 Neiner, C. Monin, D. Leroy, B. Mathis, S. Bohlender, D. gamma Peg: testing Vega-like magnetic fields in B stars |
topic_facet |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
description |
gam Peg is a bright B pulsator showing both p and g modes of beta Cep and SPB types. It has also been claimed to be a magnetic star by some authors while others do not detect a magnetic field. We aimed at checking for the presence of a field, characterise it if it exists or provide a firm upper limit of its strength if it is not detected. If gam Peg is magnetic, it would make an ideal asteroseismic target to test various theoretical scenarios. If it is very weakly magnetic, it would be the first observation of an extension of Vega-like fields to early B stars. Finally, if it is not magnetic and we can provide a very low upper limit on its non-detected field, it would make an important result for stellar evolution models. We acquired high resolution, high signal-to-noise spectropolarimetric Narval data at TBL. We also gathered existing dimaPol@DAO and Musicos@TBL spectropolarimetric data. We analysed the Narval and Musicos observations using the LSD technique to derive the longitudinal magnetic field and Zeeman signatures in lines. The longitudinal field strength was also extracted from the Hbeta line observed with the DAO. With a Monte Carlo simulation we derived the maximum strength of the field possibly hosted by gam Peg. We find that no magnetic signatures are visible in the very high quality spectropolarimetric data. The average longitudinal field measured in the Narval data is Bl=-0.1+/-0.4 G. We derive a very strict upper limit of the dipolar field strength of Bpol~40 G. We conclude that gamma Peg is not magnetic: it does not host a strong stable fossil field as observed in a fraction of massive stars, nor a very weak Vega-like field. There is therefore no evidence that Vega-like fields exist in B stars contrary to the predictions by fossil field dichotomy scenarios. These scenarios should thus be revised. Our results also provide strong constraints for stellar evolution models. : 8 pages, accepted in A&A |
format |
Text |
author |
Neiner, C. Monin, D. Leroy, B. Mathis, S. Bohlender, D. |
author_facet |
Neiner, C. Monin, D. Leroy, B. Mathis, S. Bohlender, D. |
author_sort |
Neiner, C. |
title |
gamma Peg: testing Vega-like magnetic fields in B stars |
title_short |
gamma Peg: testing Vega-like magnetic fields in B stars |
title_full |
gamma Peg: testing Vega-like magnetic fields in B stars |
title_fullStr |
gamma Peg: testing Vega-like magnetic fields in B stars |
title_full_unstemmed |
gamma Peg: testing Vega-like magnetic fields in B stars |
title_sort |
gamma peg: testing vega-like magnetic fields in b stars |
publisher |
arXiv |
publishDate |
2013 |
url |
https://dx.doi.org/10.48550/arxiv.1312.3521 https://arxiv.org/abs/1312.3521 |
long_lat |
ENVELOPE(-57.955,-57.955,-61.923,-61.923) |
geographic |
Gam |
geographic_facet |
Gam |
genre |
narval narval |
genre_facet |
narval narval |
op_relation |
https://dx.doi.org/10.1051/0004-6361/201323093 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1312.3521 https://doi.org/10.1051/0004-6361/201323093 |
_version_ |
1766244475906031616 |