Long‐term activity of QU Car

Abstract

This paper presents an analysis of the long‐term activity of the cataclysmic variable (CV) QU Car using CCD (charge‐coupled device) V‐band ASAS (All Sky Automated Survey) data, obtained between 2001 and 2009. I show that the evolution of brightness on the timescale of weeks and months (not from night to night) dominates the light curve during this mapped time. The histograms of brightness are not consistent with the normal distribution and show that the character of the light curve changes for the individual years, although the mean brightness remains similar. One episode of an exceptionally bright state displayed a return accompanied by a series of strong fluctuations of brightness. This shows that the amplitude of the brightness variations changes from time to time, and it does not always depend on the mean level of brightness. This analysis of QU Car thus shows the type of the long‐term activity in a CV with a very high mass transfer rate.