ИСТИНА

The aim of this paper was to analyze UBV observations of HZ Her/Her X-1 obtained since 1988 up to now. The large volume of photometric data has been accumulated, permitting detailed studies of the caracteristics of the optical star and accretion disc. The particular attention has been given to analysis of photoelectric UBV and CCD observations of HZ Her during the anomalous low state of X-ray flux in 1999. These data were mostly obtained on the binary phases 0.93-1.07 (X-ray eclipse). Our new observations has been analyzed together with the previous ones to find some peculiarities in the optical behavior of HZ Her during anomalous low states and variations in accretion disk structure. The orbital main on-state and anomalous low state light curves has been compared. We have found that the light curve of this system in anomalous low state is considerable different from the mean light curve of HZ Her. These differebces can be explained by the temperature and dimensions variations of the hot spot on the optical star side that irradiated by X-rays from pulsar. The 1999 data are clearly show that the brightness of accretion disc in HZ Her at the X-ray eclipse ingress/egress has been 6-10 times lower than the average brightness of this system in the main on-state reported in earlier study of Voloshina and Lyuty (1989). The changes in conditions of the X-ray irradiation of the optical star in Her X-1 were also considered.