SOFT-X-RAY EMISSION FROM INTERMEDIATE-AGE OPEN CLUSTERS - IC-4651

We present the results of soft X-ray observations of the intermediate- age open cluster IC 4651 performed with the ROSAT PSPC. We detected 25 sources. Two are identified with a giant binary and a blue straggler respectively, both belonging to the cluster, and two with probable mai n-sequence members. Two other cases have ambiguous identification. Of the five binaries known in the cluster, the one detected in X rays is the only one whose period is short enough to maintain fast rotation an d therefore strong stellar activity at a high age. The detected blue s traggler is probably binary, suggesting that binarity is the key to pr oducing a high level of X-ray emission. It is the third blue straggler detected in X rays. The remaining sources need to be identified throu gh optical follow-up.