The ultraviolet variability of the symbiotic star HBV 475. II. Study of line flux variations.

The symbiotic star HBV 475 (= V1329 Cyg) is one of the few symbiotics where periodic variations in the ultraviolet line fluxes have been observed. The authors collect the IUE observations between June 1979 and December 1984. Extending the work of Nussbaumer and Schmutz (1983), who presented a detailed study of this object, the authors establish the periodicity in the ultraviolet line and continuum fluxes and in velocity shifts. There can thus be no doubt about the binary nature of this object. The line flux variations result in a period of 975 days.