Measuring stellar rotation periods with Kepler K2 light curves

Our aim is to measure stellar rotation periods from the Kepler K2 Campaign 2 light curves to study the evolution of stars’ angular momentum content. Our primary targets are members of the ~10 Million year-old cluster, Upper Scorpius: by comparing the rotation periods we measure for young stars in Upper Sco to those measured for stars in older clusters, we can better understand how stars spin up as they approach their main sequence radii, and help develop an age diagnostic for stars that are not in clusters. We measured rotation periods for by calculating an autocorrelation function for the Kepler K2 light curve of each of our targets. The autocorrelation function identifies the presence of periodic structures in a light curve by measuring the degree of similarity between the light curve and a copy that has been shifted by some time t. To measure the period for each target, we search the autocorrelation function for the shift t that maximizes the similarity of the light curve and its time-shifted copy. We summarize the current state of our period measurement algorithm and describe plans for further development