ON THE PROBLEM OF VERY ENERGETIC FLARES IN BINARY-SYSTEMS

Observations of several RS CVn and other late-type binary systems have revealed the occurrence of extremely energetic flares ranging from 10 (34) UP to 10(38) erg. The energy of these flares has commonly been ex plained by the presence of a filament that can, due to the binary natu re of the system, store much more energy than a filament on a single s tar for the same surface field strength.Here, we show that this explan ation is based on an unphysical model and we briefly analyse different mechanisms that could in principle account for these flares. Followin g previous authors, we suggest that either the flares are scaled-up ve rsions of solar type flares due to a larger amount of magnetic flux in volved in the eruption, or they are resultant from the interaction bet ween the magnetospheres of the two stars.