QUASI-PERIODIC LIGHT VARIATIONS IN 4 HERBIG AE BE STARS/

The results of long-term photoelectric UBVR observations of four Herbi g Ae/Be stars (V1331 Cyg, MWC 342, V633 Cas, and MWC 297) are presente d. These objects exhibited variability in the range 0(m).15 to 0(m).8. Smooth light variations on a time scale of 70-140 days were observed. A rapid irregular variability with an amplitude of 0(m).1-0(m).2 was superimposed on these variations. The long-term monitoring of MWC 342, V633 Cas, and MWC 297 also revealed smooth variations in the mean bri ghtness from year to year. The results of a search for periodic light variations are reported. The time series are analyzed by the CLEAN met hod. Quasi-periods that varied over the range 10 to 50 days were detec ted in all four stars. Only V633 Cas showed a stable period of 35.5051 , which was observed in the entire interval of observations. The obser ved period variability may reflect a spatial origin of these periodici ties. It is assumed that the periodicities could be associated with hi gh-latitude clouds of gas and dust.