RADIO-CONTINUUM AND X-RAY-PROPERTIES OF THE CORONAE OF RS CANUM-VENATICORUM AND RELATED ACTIVE BINARY-SYSTEMS

We present some new radio continuum and X-ray data on the coronae of RS CVn and related active binary systems which complement those included in the previous Drake, Simon, and Linsky study of the radio emission properties of these stars. The bulk of these new radio data consists of 6 cm circular polarization measurements of 28 binaries for which we can set significant constraints (less than or similar 25%) on this quantity. Seven sources showed definite circular polarization at levels from 2% to 13%, and two others showed possible circular polarization. We also present 2 cm flux density and circular polarization measurements for 29 Dra, lambda-And, and sigma-Gem on dates for which we also have 6 cm observations. The 2 to 6 cm spectral indices for these sources range from +0.62 (lambda-And during a radio flare) to -0.5 (sigma-Gem at a low flux density level). We present new optical positions of 1" accuracy from the Hubble Space Telescope Guide Star Catalog for 8 RS CVn systems which previously had very inaccurate positional information. Comparison of these optical positions with our previously reported radio observations of these stars confirms the claimed detections of UX Com, VV Mon, and UZ Lib, disproves the possible detection of SS Boo, and transforms the nondetections of WY Cnc and PW Her into definite detections of 0.46 +/- 0.05 and 0.78 +/- 0.05 mJy, respectively. The X-ray data presented here are based on a search of the Einstein IPC Slew Catalog at the positions of 190 RS CVn and related active binary systems. We have found 49 X-ray sources at the 190 positions examined (a 26% success rate) in the IPC Slew Catalog, of which 12 appear to be new IPC sources. We have used these new X-ray data, together with those previously reported in Drake, Simon, and Linsky, to reexamine the correlations between X-ray emission and radio emission, and between X-ray emission and other stellar parameters, and find no major changes in those earlier results. Finally, in the light of the radio and X-ray emission properties of RS CVn binaries described herein, we reexamine the various proposed theoretical explanations for the emission mechanisms in these two wavelength regions.