Vol 100, No 7 (2023)

A list of candidates for binary supermassive black holes, compiled from available data on optical band variability and emission spectrum shape, has been analysed. An artificial neural network has been constructed to estimate the radiation fluxes at the frequency 240 GHz. For those candidates of binary supermassive black holes for which the network building procedure proved possible, the criterion of possibility to observe the source at the Millimetron Space Observatory was tested. The result of this study is presented as a table of 17 candidates for binary supermassive black holes. Confirmation (or refutation) of the binarity of these objects by means of observational data commited on a space interferometer with parameters similar to those of the Millimetron Space Observatory will be an important milestone in the development of the theory of galaxy formation.

The results of a study of the variability of maser emission in OH lines in the 18 cm range in the G10.624–0.385 star formation region from monitoring data performed at the Large Radio Telescope in Nançay (France) in 2008–2023 are presented. It is obtained that for a Zeeman pair in line 1667 MHz splitting (about 1.96 km/s) and, consequently, the magnitude of the longitudinal magnetic field have been stable for more than 25 years. In the satellite lines of 1612 and 1720 MHz, broadband absorption and emission are observed, respectively. Mirrored The profiles of the OH 1612 and 1720 MHz satellite lines indicate that the levels of the corresponding transitions are pumped by IR radiation from a source immersed in a magnetized molecular cloud around the OH maser. Spatial identification of details in both main lines is carried out. It is found that the transverse magnetic field is directed mainly along some organized structure in the form of an arc.

Based on photometric observations published in the literature, the manifestations of the activity of the K2V dwarf HD 166620 were studied. The obtained results are compared with the results of the analysis of the chromospheric activity of the star. HD 166620 is entering in a long magnetic minimum and may be the first reliable candidate for objects that are at a minimum of activity similar to the Maunder minimum (MM) of the Sun. Studies of changes in the magnetic activity of the star were carried out based on the values of the S‑index (1885 measurements in the observation interval for 53.6 years), obtained mainly before its entry into the MM phase, and on photometric measurements of the brightness in the b and y filters covering 17 seasons from 1993 to 2020 obtained with the automatic APT telescope (MM phase and its beginning). It has been established that the Kamogata Wide-field Survey observation data combined into a single array in filters B, V and Ic (about 1400 measurements) convincingly demonstrates the long-term variability of the HD 166620 brightness in the phase of the probable MM state. At the same time, the observations of the Kamogata Wide-field Survey fill the gap in the photometric data of the APT automatic telescope well. The value of the cycle (about 4000 days) is comparable to the duration of observations, with its refinement by according to the data of a larger time interval, it is possible that it will correspond more to the value found from the data on chromospheric activity. The main results of the work should include the cyclic long-term changes in the activity of the star detected by us during the beginning of the MM phase. The question of clarifying the value of the rotation period HD 166620 remains open. There were no significant peaks corresponding to the value P = 45.06 days, previously accepted as the period of rotation of the star, on almost all the power spectra constructed by us. It is noted that further observations are required to establish the full duration of the minimum phase of the star’s activity.

A brief outline of the development of ideas and a review of some achievements in modern celestial mechanics are given. The emphasis is on the fact that the classical definition of this science given by Laplace does not fully reflect the content of modern celestial mechanics, and the term dynamic astronomy is more capacious. Dynamic astronomy studies almost everything that moves and rotates in space: from dust particles to comets and asteroids, from satellites, planets and their satellites to stars and galaxies. This complex science includes not only the problems of classical, but also relativistic celestial mechanics, it includes the theory of equilibrium figures, various computational methods and computer simulation methods. Qualitative methods are of great importance, the culmination of which was the creation of the KAM theory. The development of celestial mechanics went through the practice of various applications, and the range of problems in it is exceptionally wide. A striking stimulus for the development of dynamical astronomy was the discovery of exoplanets around other stars. The article traces a chain of ideas from Keplerian orbits to osculating Lagrangian ellipses, from two-body problems to many-body problems, from Gaussian rings to models built on the basis of precessing analogues of these rings.