A search for radial velocity variations in the blue stragglers of NGC7789.

Image-tube spectra have been obtained for seven bright, blue stragglers in NGC 7789. Statistical tests applied to the data indicate that these stars do not have radial velocity variations greater than the detection limit of ≡12 km s^-1. Corrections have been made for possible semiamplitudes smaller than this limit. The corrected possible binary frequency is about the same or less than the frequency observed in open clusters for stars of these early spectral types. The conclusion is that, although some stragglers may be binaries, duplicity, or at least close duplicity, is unlikely to be a necessary condition for the existence of all blue stragglers.