Stellar Rotation in Kepler: Forward Modeling of the Kepler Period Distribution

The Kepler mission has made it possible to detect the signatures of surface rotation in tens of thousands of stars across many different spectral types, ages, and evolutionary states. While it is tempting to use these rotation rates as a means to determine the ages of field stars in Kepler via the gyrochronology relationships, we show that 1) only a fraction of these stars should be viable targets for the existing period-age relationships due to “contamination” from hot stars and subgiants, and 2) that apparent age trends in the rotation distributions can be explained with an activity-based detection bias. We have performed a forward modeling exercise in an effort to reproduce the observed distribution of rotation periods.