Intereclipse Spectroscopic Snapshot of ϵ Aurigae with the Hubble Space Telescope

Abstract

ABSTRACTA single‐epoch low‐resolution Goddard High Resolution Spectrograph spectrum of the eclipsing binary ϵ Aurigae was obtained while the secondary was orbiting toward eclipse by the primary. The spectrum as recorded between 1175 and 1461 Å is rich with emission and absorption lines which include stellar and interstellar components. The emission‐line profiles have the appearance of double‐peaked emission with a stronger red component at a radial velocity of +108 km s−1, an overlying unresolved absorption component at −20 km s−1, and a weaker blue emission bump at ∼−92 km s−1. We compare these observational results with known orbital properties of the ϵ 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.