Inter-Eclipse Spectroscopic Snapshot of Epsilon Aurigae with HST

Abstract

A single-epoch low resolution GHRS spectrum of the eclipsing binary Epsilon Aurigae was obtained while the secondary was orbiting towards eclipse by the primary. The detected emission line profiles have the appearance of double- peaked emission with a stronger red component at a radial velocity of +108 km/s, and a weaker blue emission bump at ca. -92 km/s. We compare these observational results with known orbital properties of the epsilon Aur binary system, and propose that the emission originates at the inner radius of the disk surrounding the enigmatic secondary. We interpret the kinematic data as a possible means to uncover the underlying stellar masses and we speculate about the binary's relationship to other "high-mass" models.