Quasi-periodic oscillations in the cataclysmic variable KR Aurigae

Abstract

We represent fast photometric observations of KR aurigae, a nove-like variable, made during 1984-1988, in the B and U bands. The light curves show large-amplitude pulsations with periods in the range 480-780 s. the period is found to be different even on consecutive nights and, therefore, these pulsations are interpreted as “quasi-periodic” in nature. The pulsation periods in the bright state are positively correlated with the source intensity, but the low-state periods do not follow this linear trend. We discuss possible explanations of the quasi-periodic oscillations. Pulsations with period in the 1050-1600 s range are also found in the data, which can be attributed to broader features seen in the light curves. We also present the X-ray results from analysis of the observations made with the Einstein Observatory. The X-ray spectrum is found to be soft with a large hydrogen column density.