SPECTROSCOPIC OBSERVATIONS OF D-TYPE SYMBIOTIC STARS

Observations of five D-type symbiotics are presented: three oxygen Mir a (He2-38, H2-38 and H1-36) and two carbon Mira symbiotics (AS 210 and SS 38). The observations in the spectral range between 3200 Angstrom and 7400 Angstrom show the presence of several emission lines in vario us states of excitation. A line list is provided with their suggested identifications. Several parameters were derived for each object: inte rstellar reddening as determined from Balmer decrement and He Ir lines , temperature and electronic density, abundance ratios of Ne/O, Ar/O, Fe/Ne, N/O and He/H. We found nitrogen enrichment while for the other elements their abundances are compatible with solar, except iron which is depleted. We did not detect significant changes in the line and in the continuos spectra of the stars analyzed here, except for He2-38, which increased its degree of excitation compared to Alien's (1984) ca talogue.