Publication details

Unraveling the variability of sigma Ori E

Authors

OKSALA Mary Elisabeth KOCHUKHOV Oleg KRTIČKA Jiří PRVÁK Milan MIKULÁŠEK Zdeněk

Year of publication 2015
Type Article in Proceedings
Conference New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry
MU Faculty or unit

Faculty of Science

Citation
Web http://adsabs.harvard.edu/abs/2015IAUS..307..348O
Doi http://dx.doi.org/10.1017/S1743921314007066
Field Astronomy and astrophysics
Keywords stars: magnetic fields; stars: rotation; stars: early-type; stars: circumstellar matter; stars: individual: HD 37479; techniques: spectroscopic; techniques: polarimetric; ultraviolet: stars
Description Sigma 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 sigma 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 sigma 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.

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