Optical and UV observations of the symbiotic star CH Cygni after the jets ejection in 1984

Abstract

The optical and UV observations of the symbiotic star CH Cyg are discussed in the context of the jet appearance. CH Cygni is an eclipsing binary with a period of 5700 days, consisting of an M 6 giant and a white dwarf surrounded by an accretion disk formed from the cool giant wind. Previous studies of the system are reviewed and emission line profiles before, during, and after the eclipse are presented. It is suggested that a part of the disk material is ejected perpendicular to the disk plane. Since the disk is seen edge-on, the decreasing of the emitting surface is observed as a drop in brightness.