Radial velocities of stars in NGC 2264

We report radial velocities for 695 stars, of which approximately 407 stars are confirmed or very likely members. Our results more than double the number of members with radial velocities from Furesz et al., resulting in a much better defined kinematic relationship between the stellar population and the associated molecular gas.

In particular, we find that there is a significant subset of stars that are systematically blueshifted with respect to the molecular (^13^CO) gas. The detection of Lithium absorption and/or infrared excesses in this blueshifted population suggests that at least some of these stars are cluster members; we suggest some speculative scenarios to explain their kinematics. Our results also more clearly define the redshifted population of stars in the northern end of the cluster; we suggest that the stellar and gas kinematics of this region are the result of a bubble driven by the wind from O7 star S Mon.