The time depending offset between the center of brightness and center of mass of the comet nucleus has been determined on the ground of positional observations of the comet. It is assumed that the offset is caused by the motion of particles ejected from the nucleus. The dynamic model of particles motion in the vicinity of the comet nucleus was developed. Calculations showed that the size of the particles should be about 53 m in diameter and had the initial velocity of 1.2 m/s at the moment of outburst. Within 20 days after the explosion the size of particles decreased to about 5 mm. The motion of these particles allowed subsequent offset between the center of brightness and center of mass of the comet nucleus to be obtained from positional observations.