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Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317.

Authors :
Buysschaert, B.
Neiner, C.
Briquet, M.
Aerts, C.
Source :
Astronomy & Astrophysics / Astronomie et Astrophysique. Sep2017, Vol. 605, p1-16. 16p.
Publication Year :
2017

Abstract

Large-scale magnetic fields at the surface of massive stars do not only influence the outer-most layers of the star, but also have consequences for the deep interior, only observationally accessible through asteroseismology. We performed a detailed characterization of the dipolar magnetic field at the surface of the B3.5V star HD43317, a SPB/β Cep hybrid pulsator, by studying the rotationally modulated magnetic field of archival and new Narval spectropolarimetry. Additionally, we employed a grid-based approach to compare the Zeeman signatures with model profiles. By studying the rotational modulation of the He lines in both the Narval and HARPS spectroscopy caused by co-rotating surface abundance inhomogeneities, we updated the rotation period to 0.897673 ±0.000004 d. The inclination angle between the rotation axis and the observer's line of sight remains ill-defined, because of the low level of variability in Stokes V and deformations in the intensity profiles by stellar pulsation modes. The obliquity angle between the rotation and magnetic axes is constrained to β ∈ [67; 90]°, and the strength of the dipolar magnetic field is of the order of 1 kG to 1.5 kG. This magnetic field at the stellar surface is su°ciently strong to warrant a uniformly rotating radiative envelope, causing less convective core overshooting, which should be visible in future forward seismic modeling. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00046361
Volume :
605
Database :
Academic Search Index
Journal :
Astronomy & Astrophysics / Astronomie et Astrophysique
Publication Type :
Academic Journal
Accession number :
127655111
Full Text :
https://doi.org/10.1051/0004-6361/201731012