INTEGRAL X-ray source IGR 21343+4738: spectral and photometric variability research of the optical component

The preliminary results of photometric and spectroscopic monitoring of the optical component of the hard X-ray source IGR 21343+4738 by the RTT-150 telescope are presented. For the first time, estimates of the system's orbital parameters have been obtained: the $\gamma$-velocity is $-70$ km/s, the semi-amplitude of radial velocity curve is $K=10$ km/s, and the system's orbital period is $40$ or $80$ days. A preliminary analysis of photometric variability on different time scales (hours, days, months, and years) is completed.