Extreme-ultraviolet flares in an F2 star

We report on the coronal properties of two early F dwarfs. I;or both stars, spectroscopic data reveal a hot corona with material at temperatures as high as 10(7.1)-10(7.2) K. Th, EUV photometric observations of one of the stars (HR 120: F2) reveal two large flares with rapid decay times. The rapid decays are in striking contrast with previously published slowly decaying flares on a late type F star (HR 1817: F8/9). Analysis of decay times suggests that the loop sizes which flared in the F2 star are significantly shorter than those which flared in the F8/9 star. We discuss these results in the context of a proposal made by Giampapa & Rosner.