The magnetic field topology and chemical abundance distributions of the Ap star HD 32633
Previous observations of the Ap star HD 32633 indicated that its magnetic field was unusually complex in nature and could not be characterised by a simple dipolar structure. Here we derive magnetic field maps and chemical abundance distributions for this star using full Stokes vector (Stokes $IQUV$)...
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ftdatacite:10.48550/arxiv.1508.00224 2023-05-15T18:50:48+02:00 The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 Silvester, J. Kochukhov, O. Wade, G. A. 2015 https://dx.doi.org/10.48550/arxiv.1508.00224 https://arxiv.org/abs/1508.00224 unknown arXiv https://dx.doi.org/10.1093/mnras/stv1775 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 2015 ftdatacite https://doi.org/10.48550/arxiv.1508.00224 https://doi.org/10.1093/mnras/stv1775 2022-04-01T11:59:01Z Previous observations of the Ap star HD 32633 indicated that its magnetic field was unusually complex in nature and could not be characterised by a simple dipolar structure. Here we derive magnetic field maps and chemical abundance distributions for this star using full Stokes vector (Stokes $IQUV$) high-resolution observations obtained with the ESPaDOnS and Narval spectropolarimeters. Our maps, produced using the Invers10 magnetic Doppler imaging (MDI) code, show that HD 32633 has a strong magnetic field which features two large regions of opposite polarity but deviates significantly from a pure dipole field. We use a spherical harmonic expansion to characterise the magnetic field and find that the harmonic energy is predominately in the $\ell=1$ and $\ell=2$ poloidal modes with a small toroidal component. At the same time, we demonstrate that the observed Stokes parameter profiles of HD 32633 cannot be fully described by either a dipolar or dipolar plus quadrupolar field geometry. We compare the magnetic field topology of HD 32633 with other early-type stars for which MDI analyses have been performed, supporting a trend of increasing field complexity with stellar mass. We then compare the magnetic field topology of HD 32633 with derived chemical abundance maps for the elements Mg, Si, Ti, Cr, Fe, Ni and Nd. We find that the iron-peak elements show similar distributions, but we are unable to find a clear correlation between the location of local chemical enhancements or depletions and the magnetic field structure. : 15 pages, 11 figures, accepted for publication in MNRAS 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 Silvester, J. Kochukhov, O. Wade, G. A. The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
topic_facet |
Solar and Stellar Astrophysics astro-ph.SR FOS Physical sciences |
description |
Previous observations of the Ap star HD 32633 indicated that its magnetic field was unusually complex in nature and could not be characterised by a simple dipolar structure. Here we derive magnetic field maps and chemical abundance distributions for this star using full Stokes vector (Stokes $IQUV$) high-resolution observations obtained with the ESPaDOnS and Narval spectropolarimeters. Our maps, produced using the Invers10 magnetic Doppler imaging (MDI) code, show that HD 32633 has a strong magnetic field which features two large regions of opposite polarity but deviates significantly from a pure dipole field. We use a spherical harmonic expansion to characterise the magnetic field and find that the harmonic energy is predominately in the $\ell=1$ and $\ell=2$ poloidal modes with a small toroidal component. At the same time, we demonstrate that the observed Stokes parameter profiles of HD 32633 cannot be fully described by either a dipolar or dipolar plus quadrupolar field geometry. We compare the magnetic field topology of HD 32633 with other early-type stars for which MDI analyses have been performed, supporting a trend of increasing field complexity with stellar mass. We then compare the magnetic field topology of HD 32633 with derived chemical abundance maps for the elements Mg, Si, Ti, Cr, Fe, Ni and Nd. We find that the iron-peak elements show similar distributions, but we are unable to find a clear correlation between the location of local chemical enhancements or depletions and the magnetic field structure. : 15 pages, 11 figures, accepted for publication in MNRAS |
format |
Text |
author |
Silvester, J. Kochukhov, O. Wade, G. A. |
author_facet |
Silvester, J. Kochukhov, O. Wade, G. A. |
author_sort |
Silvester, J. |
title |
The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
title_short |
The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
title_full |
The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
title_fullStr |
The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
title_full_unstemmed |
The magnetic field topology and chemical abundance distributions of the Ap star HD 32633 |
title_sort |
magnetic field topology and chemical abundance distributions of the ap star hd 32633 |
publisher |
arXiv |
publishDate |
2015 |
url |
https://dx.doi.org/10.48550/arxiv.1508.00224 https://arxiv.org/abs/1508.00224 |
genre |
narval narval |
genre_facet |
narval narval |
op_relation |
https://dx.doi.org/10.1093/mnras/stv1775 |
op_rights |
arXiv.org perpetual, non-exclusive license http://arxiv.org/licenses/nonexclusive-distrib/1.0/ |
op_doi |
https://doi.org/10.48550/arxiv.1508.00224 https://doi.org/10.1093/mnras/stv1775 |
_version_ |
1766244558638678016 |