SIMBAD references

We use differential CCD photometry to search for variability in BVI among 990 stars projected in and around the old open cluster M67. In a previous paper we reported results for 22 cluster members that are optical counterparts to X-ray sources; this study focuses on the other stars in our observations. A variety of sampling rates were employed, allowing variability on time scales ranging from ∼0.3 hours to ∼20 days to be studied. Among the brightest sources studied, detection of variability as small as σ≃10mmag is achieved (with >3σ confidence); for the typical star observed, sensitivity to variability at levels σ≃20 mmag is achieved. The study is unbiased for stars with 12.5<B<18.5, 12.5<V<18.5, and 12<I<18 within a radius of about 10 arcmin from the cluster centre. In addition, stars with 10<BVI<12.5 were monitored in a few small regions in the cluster. We present photometry for all 990 sources studied, and report the variability characteristics of those stars found to be variable at a statistically significant level. Among the variables, we highlight several sources that merit future study, including stars located on the cluster binary sequence, stars on the giant branch, blue stragglers, and a newly discovered WUMa system.