Rotational velocities of O stars in clusters

Our approach is (1) to examine the observed projected rotational velocities among a large sample of newly formed stars spanning a range in mass between 0.2 and 50M_{sun}_ and (2) to search for evidence of a discontinuity in rotational properties that might indicate a difference in the stellar formation process at some characteristic mass.

Our database includes recently published values of vsini for young intermediate and low-mass stars in Orion, as well as new observations of O stars located in young clusters and OB associations.