Rotation in the Lagoon Nebula with K2

A low-mass star's rotation rate drives its magnetic field, and in the case of young stars, also affects accretion and planetary formation. Observations of the rotation rates of young stars help constrain models of star and planet formation. We present rotation rates from K2 observations of stars in the ~1-2 Myr Lagoon Nebula, one of the youngest clusters with space-based rotation rates available. From 414 light curves we obtain reliable rotation periods for 325 stars; 124 of them are disk-bearing and 201 are disk-free. This constitutes a significant increase in the collection of K2 rotation rates available for ~1-5 Myr stars. The overall distribution is broadly consistent with expectations, in that the slowest rotators are mid-K and both lower and higher masses are on average faster rotating. There is weak evidence that disked stars rotate more slowly. There are a few complex periodic variables, but they appear to be surprisingly high mass compared to prior known examples of this kind of object.