IUE low resolution observations of the symbiotic star CH Cygni in 1979-1986.

Data from IUE observations of the semiregular variable CH Cyg are presented compiled in extensive tables and graphs and analyzed with reference to theoretical models. The UV/optical continuum emission is accounted for by combining a Kurucz (1979) low-gravity A-type model atmosphere at Te = 8500-9000 K with hydrogen bound-free + free-free emission at Te = 10,000 K, and the fact that the resulting maximum bolometric luminosity is insufficient to power the jet outflow is tentatively attributed to the involvement of dust in the ejection mechanism. It is suggested that the bulk of the UV emission is produced when white-dwarf accretion-disk emission is reprocessed (via thermal bremsstrahlung) in a surrounding shell cocoon at electron density (1-100) x 10 to the 7th/cu cm and Te = 10,000-20,000 K. In this model, the features observed during the 1985 minimum would be explained by a total eclipse of the cocoon.