Ultraviolet flares from RS CVn-type stars and related systems

Ultraviolet flares have been observed from RS CVn systems fairly regularly; roughly once per few days observing time. The rise to flare peak has not been resolved, and the best available constraint implies that the rise takes place in less than 2 hours. The decays typically last 8 to 12 hours, and the decay proceeds monotonically. At best, 5 or 6 IUE psectra have been obtained during the flare decay, but all too frequently only 1 or 2 spectra. Flare models have permitted to make crude estimates of atmospheric densitites, flare volume, and total radiative and non-radiative losses.