Magnetic Activity of the Cool Companion in Symbiotic Systems

I argue that cool giant companions in most symbiotic binary systems possess magnetic activity on a much higher level than isolated, or in wide binary systems, cool giants. Based on the behavior of main sequence stars, I assume that magnetic activity and X-ray luminosity increase with rotation velocity. I then show that the cool companions in symbiotic systems are likely to rotate much faster than isolated, or in wide binary systems, cool giants. The magnetic activity of the cool giant may be observed as a global axisymmetrical mass loss geometry from the cool giant (before the hot companion influences the outflow), a stochastic mass loss process, i.e., variation of mass loss rate with time and location on the giant’s surface, and in relatively strong X-ray emission. The variation in the mass loss process from the cool giant may cause variation in the properties of jets blown by the hot compact companion. I conclude that symbiotic systems should be high-priority X-ray targets. Subject headings: binaries: symbiotic − circumstellar matter − stars: AGB − stars: magnetic fields