Migrating Waves in Solar-Type Short-Period Eclipsing Binaries

Abstract

One of the properties of RS CVn-like binaries is the presence of cyclic fluctuations, sometimes called “migrating waves”, in the V and other broad-band lightcurves. These fluctuations, perhaps due to spots, vary in amplitudes and periods, in the sense that, the longer the orbital period of the RS CVn system, the higher the amplitude of the “wave”, which may be up to 30–35% of the total light variation. Therefore, in short-period (less than one day) RS CVn binaries, these fluctuations are generally difficult to be detected. We propose to use the Wilson (1979) method for lightcurve synthesis to separate the fluctua tions from the light variation caused by geometric and photometric effects in the binary system, thus allowing a precise measurement of the amplitude and periodicity of the fluctuations which can be correlated to rotation and magnetic fields.