Eclipsing phenomena of the symbiotic star CH Cygni

Eclipsing phenomena of the inner binary with a period of 756 d in the triple symbiotic system CH Cyg may have been detected in detailed spectrophotometric observations. The eclipse of the hot component by the red giant started on 1994 October 11 and finished between 1995 January 8 and 18. The ingress duration was less than one day. The radius of the red giant is estimated to be 288+/-15Rsolar from the duration of the eclipse. Assuming the bolometric correction of the red giant (M7 III) as 4, the distance to this object is estimated to be 307+/-32 pc, which agrees well with that obtained in the observations by Hipparcos. The interstellar extinction in the direction of this object may be much lower than that in the nearby areas. It has been suggested that the outer binary system with an orbital period of about 15 yr is an eclipsing one. It seems unlikely, however, that the variation of the activity of this object with a time-scale of more than 10 yr was a result of eclipses.