ИСТИНА

Our long-term studies of the star finally led to reliable measurement of the velocity of apsidal rotation in this binary elliptical system. Our earlier measurements showed slow apsidal rotation in the system. The new refined value indicates a better agreement with the theory, although there is a slight slowdown of the apsidal rotation, which can be attributed to the inclination of the rotation axis of the main component to the orbital moment of the system. A comparison is made with other independent determinations of the apsidal rotation speed using satellite observations in the x-ray range.