For the numerical model in the range of redshifts $$0 \leqslant z \leqslant 9$$ , we examined the properties and evolution of dark matter halos using a previously proposed method of compact analysis that allows separating the influence of random and regular factors on the main characteristics of the dark matter halo. In the investigated range of redshifts, a monotonic evolution of the average values of the basic parameters of small halo structures into a central massive object is observed through sequential hierarchical merging. These basic parameters include the circular velocity $${{{v}}_{c}}$$ , the parameter $${{w}_{c}} = {{{v}}_{c}}{\text{/}}r$$ , and the mass. In the range $$3 \leqslant z \leqslant 9$$ , the parameters evolve slowly, while in the range $$0 \leqslant z \leqslant 3$$ , they evolve rapidly. The evolution of the dark matter halos formed before reionization is characterized by a slow change in their average characteristics and the properties of the halo outskirts. The important role of early-formed massive structural elements is emphasized.

The problem of calculating the electromagnetic field of a charged test particle moving in the field of a Schwarzschild black hole is considered. In the framework of the non-stationary problem, it is shown that the electromagnetic field produced by the particle moving along the radial geodesic tends to spherical symmetry as the particle approaches the event horizon.

The frequency and rate of solar nanoflares (NF) were measured in 6 coronal spectral ranges (094, 131, 171, 193, 211, 335 Å) and one, related to the transition layer (304 Å). We used SDO/AIA data obtained at solar minimum in May 2019. We analyzed the same region of the Sun, covering $$360'' \times 720''$$ field-of-view, in all channels over the same time interval of 1 hour. In all the spectral bands, to search for NF we applied the same algorithm based on the amplitude analysis of fast brightenings in AIA images. The frequency and rate of NF, as can be expected, vary significantly in different wavelengths. For threshold $$5\sigma $$ , the highest NF frequency, 207 s–1, was measured in 171 Å. The next spectral ranges are 193 Å (85% of 171 channel), 211 Å (74%), and 131 Å (63%). We have not been able to reliably measure the frequency in channels 094 Å, and 335 Å, but found that it is less than 15% of the frequency in channel 171 Å. In the 304 Å channel, we found a large number of brightenings that do not match any coronal events. However, about 40% of NF in corona have a counterpart in the 304 Å line with an amplitude higher than $$5\sigma $$ .

Calculations of angles $$\beta $$ between magnetic moments and rotation axes have been carried out for radio pulsars located at different distances from the “death line.” We have shown that these angles decrease from 36° to 10° when pulsars move to the “death line”. Such values correspond to kinematic ages from 1 to 10 millions of years. We also argue that radio luminosities of pulsars decrease for these ages. This means that radio pulsars fade out when their age increases.

The aim of this paper is to study the motion behaviour of the variable mass test particle which is moving under the various perturbation effects such as gravitational forces of the primaries, spin about their axes, the transition from the Newtonian to the beyond-Newtonian regime and also due to the Coriolis as well as centrifugal forces in the equilateral triangular configuration of the circular restricted four-body problem. After determining the equations of motion and quasi-Jacobi integral, we illustrate the locations of stationary points, their stability, Poincaré surfaces of section and periodic orbits.

This work examines the formation and evolution of meteoroid streams formed during collisions of near-Earth asteroids (NEAs) with objects in the Main Asteroid Belt (MAB). This collision scenario is considered more likely compared to collisions between NEAs, since many NEAs, by virtue of their origin, intersect the MAB region, in which the density of objects is significant compared to the inner regions of the Solar System. The resulting meteoroid streams have a number of differences from streams of cometary origin, both in terms of the formation of the stream and during further dynamic evolution. In this paper, estimates are obtained for the rate of meteoroid formation as a result of collisions of NEAs with MAB asteroids. Based on high-speed collision models and data from the DART experiment, possible particle size and velocity distributions are obtained. Numerical modeling of the dynamics of the resulting meteoroid stream was carried out, considering gravitational disturbances and radiation forces, and the influence of the initial emission velocity on the evolution of the stream was studied. An analysis of the rate of dust production was carried out considering the distribution of the current NEA population, and it was concluded that the rate of influx of meteoroids of asteroid and comet origin (in mass terms) can be quite comparable.

Synthesis methods for light and radial velocity curves are currently one of the main tools for studying close binary systems (CBSs). The paper gives a brief review of the history and development of the methods and their implementations in Sternberg Astronomical Institute of Moscow State University (SAI MSU), where a set of computer programs has been created to analyze observations of CBSs of various types. As a demonstration, we present the results of the analysis by our algorithms for three interesting CBSs at different evolutionary stages. An analysis of the unusual light curves of the recently discovered pre-cataclysmic binary GPX-TF16E-48 was performed using the Roche model with spots on the normal star. The X-ray light curves of the microquasar SS433 were analyzed using a precessing accretion disk model. The highly elliptical Wolf‒Rayet binary WR22 was studied in the frame of the Roche model accounting for the absorption by the powerful wind of the Wolf–Rayet star using space-based photometric observations. As a result of this detailed analysis of the light curves and involving spectroscopic information, the parameters of the CBSs and their components were found. This paper is based on a presentation made in the astrophysical memorial seminar “Novelties in Understanding the Evolution of Binary Stars”, dedicated to the 90th anniversary of Professor M.A. Svechnikov.

Long-period eclipsing binaries (variables) are a valuable source of data for calculating stellar masses. Such objects have a sufficient amount of both photometric and spectral data for determining their parameters and further analysis. We began a project to study long-period massive eclipsing binaries in order to determine their component masses and refine the mass-luminosity relation for stars of high and intermediate masses. We describe our project in general terms, focusing in more detail on the use of large photometric surveys as an important base in our research. We will talk about almost all avaliable large sky surveys, from which we collected all available photometric data on our objects and constructed light curves. We present the results of photometric data analysis for the objects we study using existing and specially constructed software packages. In particular we demonstrate several cases, where application of the surveys’ data to our objects allows us to obtain new orbital period for eclipsing binaries. The paper is based on a talk presented at the astrophysical memorial seminar “Novelties in Understanding the Evolution of Binary Stars”, dedicated to the 90th anniversary of Professor M.A. Svechnikov.

Models of neutron stars are considered in the case of a uniform density distribution. An algebraic equation, valid for any equation of state, is obtained. This equation allows one to find the approximate mass of a star of a given density without resorting to the integration of differential equations. The solutions presented in the paper for various equations of state, including more realistic ones, differ from the exact solutions obtained by the numerical integration of differential equations by at most ~20%

The fundamental properties of a known form of life are briefly considered, including the fundamental ideas about the chemical evolution of matter and the properties of living matter, which are based on biogeochemistry and molecular biology. The concepts underlying the modern understanding of the origin of life based on chemical and biological evolution are discussed. The basics of astrobiology and the intriguing problem of the existence of extraterrestrial intelligence and the search for life in the Universe are briefly touched upon.