Time-resolved EUVE and ASCA Spectroscopy of the Spotted RS CVn Star EI Eridani

We present the results of a coordinated EUVE and ASCA campaign to study variability and flaring on the spotted RS CVn binary system EI Eridani (P_orb=1.95 d) in January 1998. The EUVE observation of 200 ks lasted from Jan. 26 - Feb. 7, and overlapped the 150 ks ASCA observation of Jan. 28 - Feb. 1. Five distinct, large-scale flares were observed with the EUVE, while only one large flare was detected in the ASCA observation. The ASCA flare represents a factor of ~ 3.5 enhancement over the non-flaring emission, compared with an enhancement of ~ 2 in the coincident EUVE flare. The flares observed during the EUVE observations showed a linear correlation between e-folding rise and decay times, as demonstrated by Osten & Brown 1998 for other RS CVn systems, with flare rise times comparable to decay timescales. Time-resolved spectroscopy of the quiescent and flaring plasmas is performed. We construct emission measure distributions and investigate abundance and density variations of the plasma during flaring and non-flaring states.