12. Environments of Active Close Binaries. I. ER Vulpeculae.
Gunn A. G. & Doyle J. G.,
A & A, 1997, 318, 60.
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ABSTRACT. High-resolution observations of the eclipsing active close binary system ER Vulpeculae have revealed excess emission in the Halpha, the Ca II IRT and the Mg Ib lines and excess absorption in the He I D3 line. The emission appears to be from a global phenomenon with the secondary component the more active. Analysis has revealed that the emission arises in plage-like material covering perhaps half of the secondarys surface. This gives credence to X-ray and UV studies which have indicated that ER Vul is near the saturation limit for dynamo-induced activity. No firm spectroscopic evidence for the existence of extended material around ER Vul was found. A consistent velocity offset of ~10km/s was observed in the excess Halpha emission from the secondary component which may be associated with active regions such as spicules. If so this represents the first observation of the equivalent of solar spicule emission in a stellar system other than the Sun.