On the problem of V1916 Cygni and the evolutionary stage of the symbiotic stars.

A spectrophotometric study of V10l6 Cygni (= MHa 328-116) has been carried out using several objective-prism spectra taken during 1971-1972, covering the spectral range 3425-9000 A. No spectral variations have been detected during this period, which indicates that this object has reached a stationary phase. The optical continuum is in agreement with that measured by O'Dell in 1965-1966. Special attention was paid to the optical and infrared energy distribution of V1016 Cyg, and to the comparison with two other strong infrared sources, V1 329 Cyg (= HBV 475) and Carinae. It is shown that the recent history of V1016 Cyg can be best represented by a model of an evolved star surrounded by a large gas and dust envelope of few hundredths of a solar mass. Before the 1964 outburst the star should have presented a cool atmosphere which was pushed out during the active phase. It is concluded that the phenomenon of the symbiotic stars could be interpreted as a manifestation of advanced stages of a very late star. Subject headings: circumstellar shells - combination spectra - spectrophotometry