Analysis of the white-light flickering of the intermediate polar V709 Cassiopeiae with wavelets and Hurst analysis

Abstract

We characterize the flickering observed in the optical lightcurve of the Intermediate Polar system V709 Cas by determining its position in the alpha-Sigma as in the Fritz and Bruch (1998) classification scheme. Sigma represents the strength of flickering at a given timescale, while alpha describes the energy distribution of the flickering at different time scales. Here alpha is independently obtained with both the wavelets and the Hurst R/S analysis. The flickering shows self-similarity in the time scale ranging from tens of minutes down to 10 seconds with stochastic persistent memory in time. alpha and Sigma appear anticorrelated. In the alpha-Sigma diagram V709 Cas falls in the region of magnetic systems. Since V709 Cas shows the spin period of the magnetic WD only in the X-ray but not in the optical, we conclude that this method can be used to characterize CV subtypes especially when their classification is uncertain.