Short time-scale variations of Epsilon Aurigae in the H-alpha region

During the total eclipse of ε Aur, 18 spectra in the Hα region were taken in rapid succession on 1983 March 9, and 6 spectra on March 10, with the Reticon at the Coudé focus of the McDonald Observatory 2-metre telescope. The data were processed and plotted by computer. Variations on short time-scales were observed in the radial velocities of the metallic lines and Hα. The radial velocities of individual metallic lines are between 3 and 16 km/s more negative than calculated from the orbital elements. The Hα has 3 emission features with equivalent widths 300 mÅ, 54 mÅ and 1 mÅ and 1 absorption feature with an equivalent width of 1800 mÅ. The profile and the equivalent widths changed only slightly while substantial variations occurred on the blue side of the two stronger emission features. The radial velocities of the emission features are about ?60, +12 and +57 km/s; that of the absorption component is +20 km/s. The radial velocity of the strongest emission feature also varies, but by much smaller amounts than the metallic lines and the variation appears to be periodic. A model in which the secondary is a B-star surrounded by hot, active clouds is proposed.