A revised gyro-age for M67 from Kepler/K2-Campaign-5 light curves

Abstract

We revisit the photometric variability of stars in the M67 field using Kepler/K2-Campaign-5 light curves. In our previous work, we limited the search area around M67 to that of a recent ground-based study. In the present work, we expand the search area and apply a more rigorous period-finding algorithm to determine the rotation periods of 98 main-sequence cluster members from the same data. In addition, we derive periods of 40 stars from the K2SC detrended light curves. We determine the mean period of single sun-like main-sequence cluster members to be 29.6 ± 0.6 d. Assuming the periods correspond to stellar rotation, the corresponding mean gyrochronological (gyro-) age is 5.4 ± 0.2 Gyr.