Are Those Flares Periodic?

The probability of a regular pattern in observed four flares separated by 49, 51, and 44 minutes in the eclipsing binary YY Gem is considered. Two approaches are employed: the first assuming that the intervals between successive events are independent, and the second assuming that all the intermediate flares are uniformly distributed between the two end ones. The issue of a 'dead period' when the telescope is pointing off the star is addressed. The probability of a more regular pattern than the actual sample is found to be 0.0047 by the first method and 0.0069 by the second method. Generalization of the case of four flares to the case of five flares is also presented.