Raman scattering in symbiotic stars. I. Spectropolarimetric observations

We present high signal-to-noise, high-dispersion linear spectro polarimetry of the Raman-scattered 6825, 7082 Å emission lines in 27 southern-hemisphere symbiotic systems. We give continuum polarization measurements for all the targets (together with estimates of the foreground interstellar polarization), and new estimates of the red-giant spectral types in 23 systems. We confirm continuum-polarization variability in five out of eight systems with previous high-quality photo polarimetry. The Raman lines are fully resolved; although they display a wide variety of morphologies, both the intensity and polarization profiles appear basically to be triple-peaked. Spectra of five systems observed in both 1992 and 1994 show stable Raman-line intensity profiles, but with significant variations in the polarization structure.