Radial velocities and kinematic membership in the open cluster NGC 3114

Echelle spectroscopic observations for 30 bright stars in the field of the sparse open cluster NGC 3114 are presented. The sample includes main-sequen ce stars, yellow and red giants, and blue straggler candidates. Radial velo cities are derived by cross-correlations using high signal-to-noise ratio s tandard spectra as templates. The cluster mean velocity is well defined fro m eight giants and several main-sequence stars whose average is [RV] = -3.5 2 +/- 0.25 km s(-1). The membership probabilities of the observed stars are computed on the basis of the velocity distributions of the cluster and fie ld stars, and the expected percentage of contamination at each position. We classified 19 cluster members and 10 nonmembers; the remaining star is a k nown spectroscopic binary for which no membership probability was assigned. Among the members, there is a bright yellow giant, seven red giants, and f our blue straggler candidates, although they should be considered as turn-o ff stars. The location of two of them in the color-magnitude diagram (sligh tly blueward of the turn-off) can be explained by their low rotational velo cities. No velocity variations were detected in the 16 stars measured more than once, which indicates that NGC 3114 possess an abnormally low binary f requency. From spectral types of cluster members, a distance modulus (V - M -v) = 9.8 +/- 0.2 mag and a reddening E(B - V) = 0.07 +/- 0.01 mag are deri ved. The cluster age is estimated to be 1.6 x 10(8) yr.