Volume 61, Nº 7 (2017)

Galactic orbits have been constructed over long time intervals for ten globular clusters located near the Galactic center. A model with an axially symmetric gravitational potential for the Galaxy was initially applied, after which a non-axially symmetric potential corresponding to the central bar was added. Variations in the trajectories of all these globular clusters in the XY plane due to the influence of the bar were detected. These were greatest for the cluster Terzan 4 in the meridional (RZ) plane. The globular clusters Terzan 1, Terzan 2, Terzan 4, Terzan 9, NGC 6522, and NGC 6558 always remained within the Galactic bulge, no farther than 4 kpc from the Galactic center.

The dynamical capture of a binary system consisting of a supermassive black hole (SMBH) and an ordinary star in the gravitational field of a central (more massive) SMBH is considered in the three-body problem in the framework of a modified Hills scenario. The results of numerical simulations predict the existence of objects whose spatial speeds are comparable to the speed of light. The conditions for and constraints imposed on the ejection speeds realized in a classical scenario and the modified Hills scenario are analyzed. The star is modeled using an N-body approach, making it possible to treat it as a structured object, enabling estimation of the probability that the object survives when it is ejected with relativistic speed as a function of the mass of the star, the masses of both SMBHs, and the pericenter distance. It is possible that the modern kinematic classification for stars with anomalously high spatial velocities will be augmented with a new class—stars with relativistic speeds.

Orbital-period variations of the eclipsing binaries FK Aql and FZ Del are analyzed. For each of the systems, a superposition of two cyclic variations of their orbital periods is found. FK Aql may be a quadruple system that contains two more bodies, besides the eclipsing binary, with masses M₃ ⩾ 1.75M_⊙ and M₄ ⩾ 1.47M_⊙, and the corresponding periods 15 and 82 yrs. This could also be a triple system with a third body of mass M₃ ⩾ 1.75M_⊙ and a period of the long-period orbit P₃ = 15 yrs, or with a third body of mass M₃ ⩾ 1.30M_⊙ and a period of the long-period orbit P₃ = 82 yrs. FZ Del may be a quadruple system with the additional componentmasses M₃ ⩾ 0.2M_⊙ and M₄ ⩾ 0.3M_⊙, with the periods 10.2 and 53.7 yrs. This could also be a triple system with a third-body mass M₃ ⩾ 0.2M_⊙ and a period of the long-period orbit P₃ = 10.2 yrs. In both systems, the residual period variations could be due to magnetic cycles of the secondary. The period variations of the eclipsing binary FZ Del could also be due to apsidal motion, together with the influence of a third body or the effects of magnetic activity.