Study of quiescent state X-ray emission from flare stars

Abstract

Quiescent-state X-ray emission of seven flare stars was studied as well as the relationship between the emissions of the chromosphere, transition region and corona. These X-ray emission characteristics were then compared with those of nonflaring dMe and dM stars and RS CVn binaries. The dependency of quiescent state X-ray luminosity L(x) on flare-star rotation period is discussed, as well as the similarities found between the spectra of the flare stars and the RS CVn binaries. Results indicate that the mean value of L(x) is about 2 X 10 to the 28th/ergs; energy spectra analysis of three of the stars gives the value of the corona temperature as three million K. The L(x)/bolometric luminosity distribution of the flare stars was found to be similar to that of the regular period RS CVn binaries but dissimilar to that of the nonflaring dwarf M stars. A strong correlation was found between L(x) and bolometric luminosity L(Bol), for the flare stars and regular period RS CVn binaries which is described by L(x) = 10 to the -3.23 + or - 22 L(Bol).