IUE spectroscopic investigation of interacting binary systems

The IUE observations of binaries consisting of at least one early type star, to the Algol systems, and to W Serpentis systems are discussed. The OB close binaries almost invaribly show a stellar wind. The difference between an unevolved early type system and a slightly evolved system is difficult to discern observationally and probably not meaningful in terms of Roche lobes. the zeta Aur stars show complex gas motions and shocks. Many of the Algol systems show peculiarities in their ultraviolet continua and the resonance lines, particularly Si IV, are of abnormal and variable strength. Emission lines were detected in several systems during the total eclipse. The W Ser stars are characterized by numerous strong emission lines in their ultraviolet spectra. It appears that these systems may be related to beta Lyrae as they seem to be in a phase of rapid mass transfer and their spectra show similarities to that of beta Lyrae.