A study of the flaring and quiescent X-ray and UV emission from II Pegasi

An investigation has been conducted of the rotational modulation of the transition-region UV and coronal X-ray emission for the RS CVn system II Pegasi. The X-ray light curve is dominated by a strong flare detected at orbital phase, where the minimum of the photometric wave occurred. The flare parameters derived show that the flare originates with a height greater than half the stellar radius. The characteristics of the flare are similar to those of a solar two-ribbon flare; a comparison of the midtransition region density with that in the coronal region shows a very steep pressure gradient.