RR Lyrae periods with PS1 and K2

The frequencies of the light variations were calculated by applying the Lomb-Scargle periodogram method on the K2 light curves that were prepared with the autoEAP photometry. The calculated frequencies of the stars then were compared with those given in the (Sesar et al., 2017AJ....153..204S, Cat. J/AJ/153/204) catalog and the Gaia DR3 RR Lyrae catalog.

We found that for the majority of the stars, the classification (95.6%) and the frequency determination (90.1%) of the Pan-STARRS RR Lyrae stars were consistent within 0.03d^-1^ with those that we derived from the K2 autoEAP light curves. For a significant subset of the sample, 7.4%, however, an offset of 1 or 2d^-1^ was found in the frequencies. These are the result of the sampling of the detections because Pan-STARRS observations are affected by diurnal cycles, whereas Kepler carried out measurements quasi-continuously.

We found that RRc subtypes are significantly more affected (25.3%) than RRab subtypes (3.7%) which is most likely caused by RRc stars having less sharp light curve features. Validation via space-based data will be important for future ground- based surveys, as well.