ESOSAT and IUE observations of the symbiotic binary R Aquarii during maximum and minimum

Coordinated IUE and EXOSAT observations of the symbiotic Mira R Aqr, made in June and December 1985, at phases 0.0 and 0.5 of the Mira light curve, are discussed. A weak X-ray flux has been for the first time unambiquously detected without any significant change with the Mira light curve. Also the UV spectrum of the central object has not varied, while the presence of high ionization lines (NV and HeII) in the spectrum of the jet-like feature is confirmed. The data are discussed in the light of a model in which the jet is preexisting material illuminated by the recently increased X and UV radiation from the inner edge of the accretion disk around the degenerate companion of the Mira primary.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.