A comparison of the rotational properties of T Tauri stars in Orion and Taurus

We analyse the distribution of projected equatorial velocities ( v  sin  i ) for a magnitude-limited sample of stars in Taurus, in order to assess whether this sample can contain a population of fast rotators (missed in previous photometric monitoring campaigns) similar to those recently discovered in Orion by Stassun et al. We find strong evidence, in line with the results of photometric monitoring campaigns in Taurus, that there is no such population of stars in Taurus that rotate at a large fraction of breakup velocity. We thus demonstrate that the stellar rotation distributions in the two star-forming regions are intrinsically different (with a statistical significance of this discrepancy in excess of 3 σ ), and discuss possible origins for this difference.