Description
Open clusters offer us the means to study stellar properties in samples with well-defined ages and initial chemical composition. Here we present a survey of projected rotational velocities for a large sample of mainly B-type stars in young clusters to study the time evolution of the rotational properties of massive stars. The survey is based on moderate-resolution spectra made with the WIYN 3.5m and CTIO 4m telescopes and Hydra multi-object spectrographs, and the target stars are members of 19 young open clusters with an age range of approximately 673Myr. We made fits of the observed lines HeI {lambda}{lambda}4026, 4387, 4471, and MgII {lambda}4481, using model theoretical profiles to find projected rotational velocities for a total of 496 OB stars.
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