The frequency of binary stars in the young cluster Trumpler 14

We present radial velocity data for the six brightest members of the open cluster Tr 14 based on high dispersion spectra obtained over a five night interval. None of these O-type stars appear to be spectroscopic binaries with periods of the order of a week or less, and none are speckle binaries. This binary fraction is low for O-type stars, and we suggest that the lack of primoridal hard binaries and their dynamical interactiosn may explain how the cluster has maintained a high spatial density even after several cluster crossing times.