Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★
Abstract Previous studies of the chemically peculiar Bp star 36 Lyn revealed a moderately strong magnetic field, circumstellar material and inhomogeneous surface abundance distributions of certain elements. We present in this paper an analysis of 33 high signal-to-noise ratio, high-resolution Stokes...
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Online Access: | http://dx.doi.org/10.1093/mnras/stx2487 http://academic.oup.com/mnras/article-pdf/473/3/3367/33043439/stx2487.pdf |
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croxfordunivpr:10.1093/mnras/stx2487 2024-05-19T07:50:08+00:00 Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ Oksala, M. E. Silvester, J. Kochukhov, O. Neiner, C. Wade, G. A. 2017 http://dx.doi.org/10.1093/mnras/stx2487 http://academic.oup.com/mnras/article-pdf/473/3/3367/33043439/stx2487.pdf en eng Oxford University Press (OUP) https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model Monthly Notices of the Royal Astronomical Society volume 473, issue 3, page 3367-3376 ISSN 0035-8711 1365-2966 journal-article 2017 croxfordunivpr https://doi.org/10.1093/mnras/stx2487 2024-05-02T09:29:13Z Abstract Previous studies of the chemically peculiar Bp star 36 Lyn revealed a moderately strong magnetic field, circumstellar material and inhomogeneous surface abundance distributions of certain elements. We present in this paper an analysis of 33 high signal-to-noise ratio, high-resolution Stokes IV observations of 36 Lyn obtained with the Narval spectropolarimeter at the Bernard Lyot Telescope at Pic du Midi Observatory. From these data, we compute new measurements of the mean longitudinal magnetic field, Bℓ, using the multiline least-squares deconvolution (LSD) technique. A rotationally phased Bℓ curve reveals a strong magnetic field, with indications for deviation from a pure dipole field. We derive magnetic maps and chemical abundance distributions from the LSD profiles, produced using the Zeeman–Doppler imaging code InversLSD. Using a spherical harmonic expansion to characterize the magnetic field, we find that the harmonic energy is concentrated predominantly in the dipole mode (ℓ = 1), with significant contribution from both the poloidal and toroidal components. This toroidal field component is predicted theoretically, but not typically observed for Ap/Bp stars. Chemical abundance maps reveal a helium enhancement in a distinct region where the radial magnetic field is strong. Silicon enhancements are located in two regions, also where the radial field is stronger. Titanium and iron enhancements are slightly offset from the helium enhancements, and are located in areas where the radial field is weak, close to the magnetic equator. Article in Journal/Newspaper narval narval Oxford University Press Monthly Notices of the Royal Astronomical Society 473 3 3367 3376 |
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Open Polar |
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Oxford University Press |
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croxfordunivpr |
language |
English |
description |
Abstract Previous studies of the chemically peculiar Bp star 36 Lyn revealed a moderately strong magnetic field, circumstellar material and inhomogeneous surface abundance distributions of certain elements. We present in this paper an analysis of 33 high signal-to-noise ratio, high-resolution Stokes IV observations of 36 Lyn obtained with the Narval spectropolarimeter at the Bernard Lyot Telescope at Pic du Midi Observatory. From these data, we compute new measurements of the mean longitudinal magnetic field, Bℓ, using the multiline least-squares deconvolution (LSD) technique. A rotationally phased Bℓ curve reveals a strong magnetic field, with indications for deviation from a pure dipole field. We derive magnetic maps and chemical abundance distributions from the LSD profiles, produced using the Zeeman–Doppler imaging code InversLSD. Using a spherical harmonic expansion to characterize the magnetic field, we find that the harmonic energy is concentrated predominantly in the dipole mode (ℓ = 1), with significant contribution from both the poloidal and toroidal components. This toroidal field component is predicted theoretically, but not typically observed for Ap/Bp stars. Chemical abundance maps reveal a helium enhancement in a distinct region where the radial magnetic field is strong. Silicon enhancements are located in two regions, also where the radial field is stronger. Titanium and iron enhancements are slightly offset from the helium enhancements, and are located in areas where the radial field is weak, close to the magnetic equator. |
format |
Article in Journal/Newspaper |
author |
Oksala, M. E. Silvester, J. Kochukhov, O. Neiner, C. Wade, G. A. |
spellingShingle |
Oksala, M. E. Silvester, J. Kochukhov, O. Neiner, C. Wade, G. A. Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
author_facet |
Oksala, M. E. Silvester, J. Kochukhov, O. Neiner, C. Wade, G. A. |
author_sort |
Oksala, M. E. |
title |
Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
title_short |
Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
title_full |
Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
title_fullStr |
Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
title_full_unstemmed |
Mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn★ |
title_sort |
mixed poloidal–toroidal magnetic configuration and surface abundance distributions of the bp star 36 lyn★ |
publisher |
Oxford University Press (OUP) |
publishDate |
2017 |
url |
http://dx.doi.org/10.1093/mnras/stx2487 http://academic.oup.com/mnras/article-pdf/473/3/3367/33043439/stx2487.pdf |
genre |
narval narval |
genre_facet |
narval narval |
op_source |
Monthly Notices of the Royal Astronomical Society volume 473, issue 3, page 3367-3376 ISSN 0035-8711 1365-2966 |
op_rights |
https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model |
op_doi |
https://doi.org/10.1093/mnras/stx2487 |
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Monthly Notices of the Royal Astronomical Society |
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473 |
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3 |
container_start_page |
3367 |
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3376 |
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1799468734079827968 |