Nonlinear dynamical analysis of the Blazhko effect with the Kepler space telescope: the case of V783 Cyg

摘要

We present a detailed nonlinear dynamical investigation of the Blazhko mod- ulation of the Kepler RR Lyrae star V783 Cyg (KIC 5559631). We used different techniques to produce modulation curves, including the determination of amplitude maxima, the O–C diagram and the analytical function method. We were able to fit the modulation curves with chaotic signals with the global flow reconstruction method. However, when we investigated the effects of instrumental and data processing artefacts we found that due to the technical problems of data stitching, detrending and the sparse sampling, the chaotic nature of the modulation can not be proved. Moreover, we found that a considerable part of the detected cycle-to-cycle variation of the modulation may originate from these effects. According to our results, even the four-year-long, unprecedented Kepler space photometry of V783 Cyg is too short for a reliable nonlinear dynamical analysis aiming at the detection of chaos from the Blazhko modulation. We estimate that two other stars could be eligible for similar analysis in the Kepler sample and in the future TESS and PLATO may provide additional candidates.