Low-, middle-, and high-frequency quasi-periodical oscillations in light curves of classical fuors

Abstract

Abstract UBVR-photoelectric monitoring of three classical fuors obtained at Mt. Maidanak Observatory in the 1978, 1981–1994 seasons is discussed. The monitoring data include 541, 1369, and 1323 individual observations for FU Ori, V1057 Cyg, and V1515 Cyg, respectively. Digital analysis of this prolonged homogeneous series allows us to establish that there are three kinds of quasiperiodical variation in light curves of classical fuors: 1. low-frequency oscillations of large-scale light curve with periods of about a few units of 103 days;2. middle-frequency oscillations of large-scale light curve with periods of about a few units of l02 days; and3. high-frequency oscillations of small-scale light curve with periods of about a and few units of 101 days.