Cl* NGC 5139 BPB 269775 , the SIMBAD biblio

We report a spectroscopic study of 19 photometric variables and 55 blue, yellow, and red straggler candidates in the field of ω Centauri. We confirm the cluster membership of 18 variables and 54 straggler candidates. Velocity variations are detected in 22 objects, and another 17 objects are suspected to be velocity-variable. The velocities of 11 objects vary consistently with their photometric periods, allowing their mass functions to be calculated. Among them, we find no indication of the presence of a massive degenerate component. On the basis of both photometric and spectroscopic data, we estimate that the fraction of binaries among blue stragglers may be as high as 69 per cent.