Spectroscopy of the symbiotic carbon star C-1 in the Draco dwarf galaxy.

In this paper we present the results of a spectroscopic monitoring of the object C-1 in the Draco dwarf galaxy during 1987-90. It is shown that C-1 is not a planetary nebula in the process of formation but instead a symbiotic binary, composed of a carbon giant, of unusual blue colors, and of a very hot compact companion, possibly an accreting white dwarf. The nebular regions are characterized by high electron densities and the emission lines appear to form in the carbon star atmosphere energized by the white dwarf's hard radiation. Large variations in the profile and radial velocity of the emission lines are detected, which relate to orbital motion. The orbital period seems to be relatively short. Variations have been observed in the integrated flux of emission lines, as expected for changing orbital phases.