Basic stellar parameter determination for active cool eclipsing binaries

Abstract

We examine procedures for the determination of reliable parameter sets characterizing stars in short period eclipsing binary systems of later dwarf, generally sunlike, spectral types. These stars have magnetodynamically active components and form a useful “extension to the solar laboratory”. Their much more rapid rotation than that of the Sun implies correspondingly enhanced indications of activity-particularly with relatively large maculation effects in broadband data. We concentrate on five such systems, for which we discuss new data and analyses-CG Cyg, ER Vul, YY Gem, BH Vir and UV Psc. Our main aim is to enable more reliable absolute comparisons between the basic properties of such stars and the Sun. Some indications of the ages of these binaries can also provide further pointers to the relative importance of different parameters (e.g. rotation, age, etc.), in determining stellar activity.