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Unraveling the variability of σ Ori E

Published online by Cambridge University Press:  23 January 2015

M. E. Oksala ,
O. Kochukhov ,
J. Krtička ,
M. Prvák  and
Z. Mikulášek
M. E. Oksala
Affiliation:
Astronomical Institute, Academy of Sciences of the Czech Republic, Fricova 298, 251 65 Ondřejov, Czech Republic email: [email protected]
O. Kochukhov
Affiliation:
Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala 75120, Sweden
J. Krtička
Affiliation:
Institute of Theoretical Physics and Astrophysics, Masaryk University, 611 37 Brno, Czech Republic
M. Prvák
Affiliation:
Institute of Theoretical Physics and Astrophysics, Masaryk University, 611 37 Brno, Czech Republic
Z. Mikulášek
Affiliation:
Institute of Theoretical Physics and Astrophysics, Masaryk University, 611 37 Brno, Czech Republic
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Abstract

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σ Ori E (HD 37479) is the prototypical helium-strong star shown to harbor a strong magnetic field, as well as a magnetosphere consisting of two clouds of plasma. The observed optical (ubvy) light curve of σ Ori E is dominated by eclipse features due to circumstellar material, however, there remain additional features unexplained by the Rigidly Rotating Magnetosphere (RRM) model of Townsend & Owocki (2005). Using the technique of magnetic Doppler imaging (MDI), spectropolarimetric observations of σ Ori E are used to produce maps of both the magnetic field topology and various elemental abundance distributions. We also present an analysis utilizing these computed MDI maps in conjunction with non-local thermodynamical equilibrium TLUSTY models to study the optical brightness variability of this star arising from surface inhomogeneities. It has been suggested that this physical phenomena may be responsible for the light curve inconsistencies between the model and observations.

Keywords

stars: magnetic fieldsstars: rotationstars: early-typestars: circumstellar matterstars: individual: HD 37479techniques: spectroscopictechniques: polarimetricultraviolet: stars
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 9 , Issue S307: New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry , June 2014 , pp. 348 - 352
Copyright
Copyright © International Astronomical Union 2015 

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