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

¹ Department of Astronomy, University of Padova, vicolo dell' Osservatorio 3, 35122, Padova, Italy e-mail: fabrizio.tamburini@unipd.it
² INAF–Astronomical Observatory of Capodimonte, Moiarello 16, 80131, Naples, Italy

Received: 13 January 2009
Accepted: 12 April 2009

Abstract

We characterize the flickering observed in the optical light curve of the intermediate polar system V709 Cas by determining its position in the α-Σ diagram of Fritz and Bruch classification scheme. The strength of flickering on a given timescale is represented by Σ, while α is the energy distribution of the flickering at different timescales. Here α is derived independently with both the wavelets and the Hurst R/S analysis. The flickering shows self-similarity on a timescale ranging from tens of minutes down to 10 s with stochastic persistent memory in time. The parameters α and Σ appear to be anticorrelated. In the α-Σ diagram, V709 Cas occupies 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.