THE ROSAT ALL-SKY SURVEY OF ACTIVE BINARY CORONAE .3. QUIESCENT CORONAL PROPERTIES FOR THE BY DRACONIS-TYPE BINARIES

We present X-ray observations of 35 active late-type BY Draconis dwarf binary systems and 25 evolved binary systems, similar in nature to th e RS Canum Venaticorum systems, obtained with the Position Sensitive P roportional Counter (PSPC) during the ROSAT All-Sky Survey phase of th e mission. Of this sample, 52 targets were detected in exposures of ro ughly 600 s or less. When these new data are combined with the earlier results from Dempsey et al. (1993b), this survey represents the large st sample of active binary systems observed to date at any wavelength, including X-rays. We expand our investigation of how coronal properti es (e.g., surface Bur, luminosity, etc.) correlate with stellar parame ters (e.g., rotation period, color, etc.) and confirm the conclusions of Dempsey et al. (1993b). Rotation period provides the best correlati on with X-ray surface flux with F-X similar to P-rot(-0.59+/-0.10) for the entire sample. We find no evidence for a ''basal'' or nonmagnetic X-ray flux component. We model the low-resolution pulse-height spectr a for 12 systems with two-temperature thermal plasmas. The derived tem peratures for the BY Dra systems are identical to those previously der ived for active evolved giants and subgiants in close binaries (Dempse y et al. 1993c). We also show that the dependence of temperature and e mission measures on rotation period is the same for the dwarf, subgian t, and giant binaries.