RS CVn systems: the high energy picture

The discovery of X-ray emission from RS CVn systems by HEAO-1 and subsequent surveys by the Einstein Observatory have shown that these close binaries exhibit greatly enhanced coronal activity. Here we review the main observational areas: (1) results of the X-ray surveys of RS CVn systems and other late-type stars which indicate how the X-ray luminosity is correlated with the binary period (and hence stellar rotation) and other coronal activity indicators. This will be discussed in the context of scaled models of the solar corona; (2) X-ray spectroscopy of the most active systems which show multi-temperature spectra and line emission consistent with solar abundances of the heavy elements; (3) observations of X-ray 'flare-type' activity that has been associated with several RS CVn systems. (Auth.)