Multifractal characterization as a function of timescale in the light curves with planetary signal observed by the Kepler mission

Abstract

We investigate the evolution of five multifractal indicators of the Kepler Mission light curves of the moderately young Sun-like Kepler-30 star accompanied by a three-planet system. We focus not only on the fact that the rotational modulation has multifractality properties but also on some studies on these properties based on scale. Then, we systematically investigate the dynamic behaviors of the small and large fluctuations in two types of light curves (PDC and SAP). Those fluctuations indicate that the properties of stellar noise and rotation modulation are highlighted when we apply the Multifractal Detrended Moving Average (MFDMA) algorithm. Our results also demonstrated that the multifractality of the light curve is due to both long-range correlation and broad probability density function, but the main source of multifractality is the long-range correlation. This new approach can be used to develop theoretical and computational models for various stellar magnetic activity-related phenomena and their interactions with the planets, and it can greatly simplify spot modeling from current TESS and future PLATO data.