Stellar flares 100-10^7 times more energetic than the most powerful solar flares have been detected from 9 normal F and G main sequence stars (Schaefer, King & Deliyannis 2000). Although these stars are not in close binary systems, their superflares show a remarkable similarity to the large stellar flares observed on RS Canum Venaticorum binary systems. Such flares are caused by magnetic reconnection events associated with the tangling of magnetic fields between the two stars. The superflare stars are certainly not of this class, although the mechanism may be similar. The superflares may be caused by magnetic reconnection between fields of the primary star and a close-in Jovian planet. This scenario explains the energies, durations, and spectra of superflares, as well as explain why our Sun does not have such events. Only known planetary properties and reconnection scenarios are required by this mechanism.

8 pages, 8 figures. High resolution PDF available from http://www.astro.yale.edu/ericr/