Mm/submm observations of symbiotic binary stars: implications for the mass loss and mass exchange Original Research Article

We discuss mm/submm spectra of a sample of symbiotic binary systems, and compare them with popular models proposed to account for their radio emission. We find that radio emission from quiescent S-type systems orginates from a conical region of the red giant wind ionized by the hot companion, whereas more complicated models involving winds from both components and their interaction are required to account for radio emission of active systems. We also find that the giant mass-loss rates derived from our observations are systematically higher than those reported for single cool giants. This result is in agreement with conclusions derived from IRAS observations and with requirements of models for the hot components.