ИСТИНА

Influence of the dynamical friction on the evolution of a triple hierarchical stellar systems have been studied. Hierarchical stellar systems are stable in contrary to the stellar systems with comparable distances between all three componets.We considered a motion in the frame of the general tree-body problem using the differential equations of motion with the Hamiltonian without short-periodic terms. Studed isolated triple stellar systems where we took into account the perturbations of the third order, we obtained the solution of the differential equations in which the mean motions of both components have the secular accelerations. Under the influence of perturbations of a distant component the mean motion in the near pair is slowed and vice versa. The mean motion of distant star increasing. These changes are small, but on the cosmological time interval the hierarchical systems will convert into to stellar systems in which all components have comparable distances between each other. These systems become unstable. In the general case, if we take into account a dynamical friction, the angular momentum of this system and its summary energy might be either loss or gain. The angle of the mutual inclination between these orbits is changing. This change may influence dynamical evolution of this stellar system.