High-resolution spectroscopy of the unique eclipsing binary system : epsilon Aurigae.

H-alpha and Na D line profiles of the Epsilon Aur system acquired during the eclipse of 1982-84 are presented. As in previous eclipses, the H-alpha absorption core shows striking, systematic changes in width and radial velocity. H-alpha also exhibits time-varying blueshifted and redshifted emission in the line wings. It is suggested that the H-alpha emission-wing variability is due solely to ongoing processes in the extended atmosphere of the supergiant primary. As the eclipse progresses, the Na D absorption lines deepen and widen, then decrease in size as their weak emission components strengthen. The time-development of the Na D line profiles over the duration of the eclipse is consistent with the eclipsing object being a massive, cool, rotating, gaseous disk. The observed Na D line velocities combined with derived values for the mass and spatial extent of the secondary suggest that the disk is losing material.