Magnetic activity of the cool component in symbiotic systems

Abstract

I argue that cool giant components in most symbiotic binary systems possess magnetic activity on a much higher level than isolated cool giants or those in wide binary systems. Based on the behaviour of main-sequence stars, I assume that magnetic activity and X-ray luminosity increase with rotation velocity. I then show that the cool components 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 of the cool giant (before the hot companion influences the outflow), a stochastic mass-loss process, i.e. a variation of mass-loss rate with time and location on the surface of the giant 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.