A wavelet analysis of photometric variability in Kepler white dwarf stars

Abstract This work describes a wavelet analysis of 14 Kepler white dwarf stars, in order to confirm their photometric variability behaviour and to search for periodicities in these targets. From the observed Kepler light curves we obtained the wavelet local and global power spectra. Through this procedure, one can perform an analysis in the time–frequency domain rich in detail, and so obtain a new perspective on the time evolution of the periodicities present in these stars. We identified a photometric variability behaviour in 10 white dwarfs, corresponding to period variations of ∼2 h to 18 d: among these stars, three are new candidates and seven, earlier identified from other studies, are confirmed.