MICROWAVE EMISSION FROM SOUTHERN CONTACT-BINARY STARS

We report the results of high-sensitivity 4.8 GHz observations of four southern contact-binary stars (AE Phe, YY Eri, RW Dor, and V757 Cen) made with the Australia Telescope Compact Array. None of these stars w ere detected above a 4sigma level of 0.4 mJy. A comparison of the radi o emission properties of contact binaries (derived from this study and from the literature) to those of short-period RS CVn stars, suggests that a decrease in the dynamo efficiency of binary stars as they appro ach contact may be required to explain the lower intrinsic radio lumin osity of contact binaries.