Unstable processes in magnetic cataclysmic variables

I. Case of the long-period polar QQ Vulpeculae

¹ Department of Astronomy, Odessa National University, T. G. Shevchenko park, 65014 Odessa, Ukraine e-mail: halevin@astronomy.org.ua
² Isaac Newton Institute of Chile, Odessa Branch, Ukraine
³ Crimean Astrophysical Observatory, Crimea, Ukraine e-mail: shakh@crao.crimea.ua
⁴ Isaac Newton Institute of Chile, Crimean Branch, Ukraine
⁵ Astronomical Observatory, Odessa National University, T. G. Shevchenko park, 65014 Odessa, Ukraine e-mail: il-a@mail.od.ua, astro@paco.odessa.ua

Corresponding author: A. V. Halevin, halevin@astronomy.org.ua

Received: 12 June 2001
Accepted: 21 June 2002

Abstract

We report the results of an investigation of unstable processes in the magnetic cataclysmic variable QQ Vul based on observations obtained at the 2.6-m Shain telescope and 1.25-m AZT-11 of the Crimean Astrophysical Observatory. The detected range of the short time-scale variations is likely caused by a sequence of different small flares, due to a non-coherence of this type variability. We report that there is practically no quasi-periodic variability in this system. Also, we have detected variations of the shot noise decay time during the orbital period. Investigations of the shot noise decay time allow us to estimate the physical size of the accreted blobs. Using archive data and our minima timings, the photometric period of this system is updated ().