Mixed poloidal-toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn*
International audience 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-res...
Published in: | Monthly Notices of the Royal Astronomical Society |
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ftsorbonneuniv:oai:HAL:obspm-02294162v1 2024-05-19T07:50:09+00:00 Mixed poloidal-toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn* Oksala, Mary E. Silvester, James Kochukhov, Oleg Neiner, Coralie Wade, Gregg Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Uppsala University Royal Military College of Canada 2018 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/document https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/file/stx2487.pdf https://doi.org/10.1093/mnras/stx2487 en eng HAL CCSD Oxford University Press (OUP): Policy P - Oxford Open Option A info:eu-repo/semantics/altIdentifier/arxiv/1709.08361 info:eu-repo/semantics/altIdentifier/doi/10.1093/mnras/stx2487 obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/document https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/file/stx2487.pdf ARXIV: 1709.08361 BIBCODE: 2018MNRAS.473.3367O doi:10.1093/mnras/stx2487 info:eu-repo/semantics/OpenAccess ISSN: 0035-8711 EISSN: 1365-2966 Monthly Notices of the Royal Astronomical Society https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 Monthly Notices of the Royal Astronomical Society, 2018, 473, pp.3367-3376. ⟨10.1093/mnras/stx2487⟩ [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] info:eu-repo/semantics/article Journal articles 2018 ftsorbonneuniv https://doi.org/10.1093/mnras/stx2487 2024-04-25T03:46:33Z International audience 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 HAL Sorbonne Université Monthly Notices of the Royal Astronomical Society 473 3 3367 3376 |
institution |
Open Polar |
collection |
HAL Sorbonne Université |
op_collection_id |
ftsorbonneuniv |
language |
English |
topic |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
spellingShingle |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] Oksala, Mary E. Silvester, James Kochukhov, Oleg Neiner, Coralie Wade, Gregg Mixed poloidal-toroidal magnetic configuration and surface abundance distributions of the Bp star 36 Lyn* |
topic_facet |
[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] |
description |
International audience 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 |
author2 |
Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)) Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS) Uppsala University Royal Military College of Canada |
format |
Article in Journal/Newspaper |
author |
Oksala, Mary E. Silvester, James Kochukhov, Oleg Neiner, Coralie Wade, Gregg |
author_facet |
Oksala, Mary E. Silvester, James Kochukhov, Oleg Neiner, Coralie Wade, Gregg |
author_sort |
Oksala, Mary 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 |
HAL CCSD |
publishDate |
2018 |
url |
https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/document https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/file/stx2487.pdf https://doi.org/10.1093/mnras/stx2487 |
genre |
narval narval |
genre_facet |
narval narval |
op_source |
ISSN: 0035-8711 EISSN: 1365-2966 Monthly Notices of the Royal Astronomical Society https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 Monthly Notices of the Royal Astronomical Society, 2018, 473, pp.3367-3376. ⟨10.1093/mnras/stx2487⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/arxiv/1709.08361 info:eu-repo/semantics/altIdentifier/doi/10.1093/mnras/stx2487 obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162 https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/document https://hal-obspm.ccsd.cnrs.fr/obspm-02294162/file/stx2487.pdf ARXIV: 1709.08361 BIBCODE: 2018MNRAS.473.3367O doi:10.1093/mnras/stx2487 |
op_rights |
info:eu-repo/semantics/OpenAccess |
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 |
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3367 |
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3376 |
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