DISCOVERY OF 2 SHORT-PERIOD ECLIPSING BINARIES WITH ACTIVE COMPONENTS

We present high-precision UBV(RI), photometry as well as soft X-ray li ght curves for the visual triple system HD 9770 and the visual binary HD 195434, obtained at the European Southern Observatory and extracted from the ROSAT all-sky survey, respectively. The optical photometry r evealed that in both systems one component is a very short-period ecli psing binary showing also BY Dra-type variability. We have computed ac curate orbital periods. deduced approximate physical parameters, spect ral classifications, distances and X-ray luminosities and identified w hich component of each visual system is responsible for the optical va riability. Futhermore, we find that both systems are variable in X-ray s, but no correlation with the optical variability is seen.