Rosat observations of pleiades flare stars

The X-ray data of a sample of 104 flare stars (FSs) in the Pleiades cluster region obtained by Stauffer et al. [1] on the basis of deep ROSAT PSPC observations are analyzed. If we divide the X-ray emission detected in late-type stars of the Pleiades cluster into FSs and non-FSs, we find that X-ray luminosities of stars of both groups can be considered as coming from the same parent population. Moreover, in order to classify stars in a sample of 23 late-type Pleiades stars of unknown nature discriminant analysis in a four-dimensional parameter space (log (L_x, log (L_x/L_bol), and ROSAT hardness ratios HR1 and HR2) has been used. It can be shown that the majority of these stars (16) are very likely FSs rather than non-FSs. Published in Astrofizika, Vol. 40, No. 4, pp. 545–557, October-December, 1997.