Spectroscopic and photometric studies of the symbiotic star EG Andromedae.

Optical spectroscopic observations carried out from August 1966 to January 1987 and standard UBV photoelectric photometry obtained from August 1985 to November 1989 of the symbiotic EG And are presented and discussed. The minimum observed in U, B, V at JD 2446350 should repeat with a 482.2 day period, as inferred from the present orbital elements. The H Balmer and He I lines seem to be formed in an envelope close to the binary system, where the giant M star atmosphere is excited also by the flux of a hot object (white dwarf or neutron star). In particular H-gamma absorption features were only observed around the cool star side, while H-gamma emission features were only seen around the hot star side. The whole system is embedded in a large and thick nebula and/or wind, often evidentiated by forbidden lines of forbidden O III and forbidden Ne III in the optical range. Perturbations and moving asymmetries in the UV light curves may be caused by additional sources like disk and/or streams.