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X-ray Spectroscopy of the Contact Binary VW Cephei

David P. Huenemoerder·Paola Testa·Derek L. Buzasi
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Abstract

Short-period binaries represent extreme cases in the generation of stellar coronae via a rotational dynamo. Such stars are important for probing the origin and nature of coronae in the regimes of rapid rotation and activity saturation. VW Cep (P=0.28 d) is a relatively bright, partially eclipsing, and very active object. Light curves made from Chandra/HETGS data show flaring and rotational modulation, but no eclipses. Velocity modulation of emission lines indicates that one component dominates the X-ray emission. The emission measure is highly structured, having three peaks. Helium-like triplet lines give electron densities of about 3.0E+10 - 18.0E+10 /cm^3. We conclude that the corona is predominantly on the polar regions of the primary star and compact.

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David P. Huenemoerder, Paola Testa, Derek L. Buzasi. 2006-06-28. X-ray Spectroscopy of the Contact Binary VW Cephei. https://doi.org/10.1086/507404

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