Abstract— The equator of Saturn is inclined to the orbital plane by an angle of 26.75°, and the period of revolution around the Sun is 29.45 years. Since the orbital eccentricity of Saturn is e ≈ 0.056 and Saturn passes the perihelion and the aphelion during the summer epoch in its southern and northern hemispheres, respectively, the southern hemisphere receives 25% more energy from the Sun than the

Abstract— Instrumentation for observing occultations of stars by Solar System bodies and its parameters are described. The complex is designed for observations at the AZT-2 telescope (D = 70 cm, F = 10.5 m) of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (МAO NASU); it is equipped with an optical reducer of the focal length and may also be mounted at the other telescopes

Abstract— The article shows the dominant role of the global migratory flow (GMF) \({{v}_{{gmf}}} = \left\{ {v_{{gmf}}^{R},v_{{gmf}}^{\theta },v_{{gmf}}^{\varphi }} \right\}\) in the generation of the variable magnetic field of the Sun (\(v_{{gmf}}^{R}\), \(v_{{gmf}}^{\theta }\), and \(v_{{gmf}}^{\varphi }\) are the radial, meridional, and latitudinal GMF velocity components, which correspond to the

Abstract— The results from the analysis of spectral observations in the Hα line of the active region (AR) NOAA 11024, in which the Ellerman bomb (EB) and various chromospheric surges developed, are presented. Spectral data with high spatial and temporal resolution were obtained using the THEMIS French–Italian solar telescope (Tenerife, Spain) on July 4, 2009. The observation time was 20 min. On the

Abstract Solar activity changes with about 11-year periodicity, two 11-year cycles form a complete 22-year magnetic cycle of the Sun. Solar cycle 25 has recently begun, and it is important to know in advance what and when it will be at its maximum. The paper predicts the maximal sunspot (Wolf) number in solar cycle 25 separately in the northern and southern hemispheres. The absolute value of the polar

Abstract— A new approach to the study of acoustic-gravity waves in the Earth’s atmosphere in the presence of vertical temperature inhomogeneity is proposed. Using this approach, the local AGW dispersion equation was obtained for the atmosphere with a small vertical temperature gradient. The modification of the acoustic and gravitational regions of freely propagating AGWs on the spectral plane \(\left(

Abstract— The theory of acoustic gravity waves (AGW) considers free disturbances of the atmosphere within the framework of a single-frequency approach. In this case, the theory implies the existence of two separate types of waves with different natural frequencies: acoustic and gravitational. In the single-frequency approach, wave fluctuations of density, temperature, and velocity are related to each

Abstract The asymmetry of the Fe I and Fe II lines in the solar flux spectra has been analyzed using three FTS atlases and the HARPS atlas; it was also analyzed in the spectra of 13 stars using observations on the HARPS spectrograph. Individual line bisectors of each star have been averaged to reduce observation noise. The obtained average bisectors in the stellar spectra are more or less similar to

Abstract— The purpose of the work is to describe ionospheric effects of the August 11, 2018, partial solar eclipse (SE) that occurred over the People’s Republic of China as observed via GPS technology. Solar eclipses are rare phenomena of nature. During 2–3 h, the rearrangement of processes acting at the Earth’s surface, in the atmosphere, geospace, i.e., in the Earth–atmosphere–ionosphere–magnetosphere

Abstract General relativity (GR) has a solid experimental base. However, the emergence of new experimental capabilities and independent observational information stimulates continuing tests of general relativity. The purpose of this work is to evaluate the potential of gravitational microlensing of distant sources on the stars of our Galaxy and to verify Einstein’s formula of gravitational refraction

Abstract The subject of this study is the infrasonic signal generated by a high-speed (32 km/s), high-energy (173 kt TNT), and large-sized (9.4 m) celestial body, later called the Kamchatka meteoroid, which entered the terrestrial atmosphere and exploded on December 18, 2018. The focus of the study is the parameters of the infrasonic signal launched by the Kamchatka meteoroid. The study is based on

Abstract— Within the model of a dissipative isothermal atmosphere, the attenuation of acoustic−gravity waves (AGWs) is studied on the basis of the modified Navier−Stokes and heat-transfer equations. Besides the usually considered velocity gradient, the modification of these equations takes into account the additional transfer of the momentum and energy induced by AGWs due to the density gradient. This

Abstract The second reprocessing campaign of historical observations of GNSS satellites at permanent stations located in Ukraine and in the Eastern Europe for GPS weeks 935–1708 (December 7, 1997 – October 6, 2012) was carried out in the GNSS Data Analysis Centre of the Main Astronomical Observatory NAS of Ukraine with using products updated in IGS repro2 and EPN-Repro2 campaigns – precise ephemerides

Abstract The Earth’s magnetosphere and the ambient interplanetary environment can create favorable conditions for the nonlinear process of energy release in the form of changes in the topology of the magnetic field and current systems, particle acceleration, wave generation, and sharp gradients in the parameters inherent to a substorm phenomenon. Initially, early studies substantiated the role of variations

AbstractGeneralized fitting formulas have been obtained describing the dependence “helium burning time–mass of zero-age stars” for stars belonging to populations I–III and having the corresponding masses and elemental composition. The approximation has been performed for nonrotating and rotating stars. The regularities in the obtained dependences have been revealed on the content Z of heavy chemical

AbstractThe passage of the Chelyabinsk meteoroid generated a wide variety of physical effects in all subsystems in the Earth–atmosphere–ionosphere–magnetosphere system. Earlier studies have been conducted in order to examine the Chelyabinsk meteoroid’s effects in the atmosphere, ionosphere, and the geomagnetic field. Particular attention has been given to the features of the infrasound signal generated

AbstractThe purpose of this paper is to construct basic correlation diagrams and plot the respective regression functions for the parameters of the infrasonic signals launched by the Lipetsk meteoroid. The celestial body that entered the Earth’s atmosphere at 01:16:20 UT on June 21, 2018, had the following initial parameters: 14.4 km/s speed, approximately 113 t mass, approximately 4 m size, and approximately

Abstract—One of the options for the practical application of GNSS technology, in addition to geodetic and navigation needs, is remote sensing of the atmosphere by radio signals from navigation satellites in order to improve the quality and detail of weather forecasts. The propagation of a radio signal from GNSS satellites to a ground receiving device (GNSS receiver) through a neutral atmosphere is

Abstract—The observations of the solar facula in the Ba II λ 455.403 Å line are used to construct a 3D model of the facula area by solving the inverse nonequilibrium radiative transfer problem and to investigate the fine structure of the field of unresolved velocities (microturbulence). New turbulent structures are formed in the layers of the upper photosphere. They are localized mainly between upward

Abstract—One of the varieties of firehose instability, whose cause is not the temperature anisotropy of plasma particles but the dynamic pressure of the beam, is considered. It is shown that such a generation mechanism can lead to an effective increase in low-frequency perturbations not only of the Alfven type but also of the magnetosonic type and also lead to instability not only in the finite and

Abstract—Evolution and morphological properties of the active region NOAA 9087 are analyzed based on space and ground observational data. Data on hard X-ray (HXR) and soft X-ray (SXR) were obtained from Yohkoh Telescopes (HXT and SXT) and the Geostationary Operational Environmental Satellite. Magnetograms and images in far ultraviolet were obtained from the Michelson Doppler Imager (MDI) and Extreme

AbstractThe propagation of solar cosmic rays in the interplanetary medium is considered on the basis of the kinetic equation describing the small-angle multiple scattering of charged particles. Energetic particles are assumed to be injected into the interplanetary medium by an instantaneous point-like source. The spatial-temporal distribution of the density and anisotropy of high-velocity particles

AbstractOne of the unsolved problems of cosmic ray physics is determining the nature and sources of ultrahigh energy cosmic rays (UHECRs, E > 1018 eV). The high degree of isotropy of the observed UHECR intensity caused mainly by the deviations of the UHECR trajectories in extragalactic and Galactic magnetic fields, as well as the significant uncertainty in their chemical composition (atomic mass),

AbstractA chain of events accompanying the occurrence of a substorm in the Earth’s ionosphere and magnetosphere is considered. Features of geomagnetic pulsations and mechanisms of their generation are indicated. Measurements of magnetic field fluctuations from fluxgate magnetometers, as well as the data on temperature, velocity, and concentration of electrons, and different types of ions from the PEACE

AbstractA theory on the emergence of global hydrodynamic flows of matter and the generation of global magnetic fields in the solar convective zone is proposed. The unstable profile of differential rotation plays a crucial role in it: all hydrodynamic flows on the Sun (poloidal circulation, torsion oscillations, and spatiotemporal variations of the poloidal flow) are generated due to the loss of stability

AbstractAs is known from multiyear theoretical and experimental studies, acoustic−gravity waves (AGW) determine the dynamics and energy balance of the atmospheres of planets and the Sun to a considerable extent. Linear wave perturbations in the atmosphere can be described with a system of second-order equations for the vertical and horizontal components of the perturbed velocity. It follows from this

AbstractIntegrated characteristics of a sample of 66 star-forming galaxies with extremely low oxygen abundances from the SDSS Data Release 14 are studied. The oxygen abundances were determined by the direct Te method for 42 galaxies with detected [O III] 436.3 nm emission lines and by the strong-line method for the remaining galaxies. Derived abundances 12 + log (O/H) fall within the 6.97–7.52 range

AbstractThe magnetic effect of meteors was first observed and theoretically explained back in the middle of the 20th century. The mechanisms for the magnetic effect of large celestial bodies (1–10 m and more) fundamentally differ from the mechanisms of geomagnetic field disturbances caused by meteors at ionospheric heights. The passage of a large meteoroid through the atmosphere and its explosion are

AbstractIn the case of astronomical observations from the surface of the Earth, it is difficult to obtain high resolution images due to the distorting influence of the atmosphere. There are two groups of methods for mitigating this influence. The first group does not interfere with the process of image formation and is related to the processing of already recorded images. The methods from the second

AbstractThe high-resolution fiber echelle Cassegrain spectrograph for the 2-m telescope at the Shamakhy Astrophysical Observatory (ShaFES) is described. The optical circuit and the schematic of the suspended part of the spectrograph are presented. The spectrograph operates in two modes with a spectral resolution of 27 500 and 55 000 in the 370–850 nm wavelength range. The results of its testing are

Abstract—The paper deals with the distribution of discovery dates of comets through phases of the 11‑year cycle of solar activity (SA). Four groups of comets are considered: long-period comets (LPCs) with an orbital period exceeding 200 yr, periodic comets (PCs) of Jupiter’s family, LPCs with a weak absolute brightness, and a group of LPC with perihelia near the plane perpendicular to the ecliptic

AbstractThe validity of the lambda-meter method for determining the quiet Sun velocity field using the Si I 1082.7 nm line is investigated. To this end, the intensity profiles of this line were calculated for the solar disk center by means of NLTE simulations in a three-dimensional model atmosphere describing the small-scale magnetic activity in the quiet solar photosphere. The velocity field recovered

AbstractThe subsolar point on Jupiter’s magnetosphere changes its position by an angle of approximately 26° over the orbital period of Jupiter, which induces seasonal variations in physical and optical characteristics of the planetary atmosphere. At the time close to the summer solstice for the northern hemisphere, Jupiter is in perihelion. Consequently, due to the significant orbital eccentricity

AbstractWe present the results of computations of the trajectories (the asymptotic latitude and asymptotic longitude) and the magnetic cutoff rigidity of galactic cosmic ray (GCR) particles for the airport Deblin, Poland (geographical latitude 51°33′32′′ N, geographical longitude 21°50′53′′ E) based on the numerical integration of equations of motion of charged particles of cosmic rays in the Earth’s

AbstractComprehensive modeling studies of the processes induced in all geospheres by the passage and explosion of the meteoroid near the city of Lipetsk (Russia) on June 21, 2018, have been conducted. Magnetic, electric, electromagnetic, ionospheric, and seismic effects, as well as the effects of acoustic-gravity waves have been estimated. The magnetic effect of turbulence has been shown to be insignificant

AbstractWe study the mid-infrared photometric properties of a sample of compact star-forming galaxies from the SDSS Data Release 14. The sample includes about 30 000 galaxies. The Hβ emission lines with equivalent widths EW(Hβ) > 1 nm are observed in the spectra of all selected galaxies. The selected galaxies are compact objects with angular diameters less than 6 arcsec. About 10 000 galaxies were

AbstractThe problem of anomalous meteors with diffuse view and increased size of their comas at the beginning of radiation is considered. Results from processing some meteors detected with high-sensitive observational TV systems of the Super-Isocon type during Leonid storm observations in 2002 are given. As opposed to similar cases described in literature previously, the given meteors had an increased

AbstractAccording to the data of complex 2D observations on the VTT telescope of the solar facula, a 3D model of the solar atmosphere in the facular region was obtained by solving the inverse radiative transfer problem in the Ba II 4554 A line. The magnetic field was estimated using the Stokes V profiles of the Fe I 15648 A line. The influence of magnetic field on photospheric convection was investigated:

Abstract—Comprehensive modeling studies of the processes induced in all geospheres by the passage and explosion of the meteoroid near the city of Lipetsk (Russia) on June 21, 2018, have been performed. Thermodynamic and plasma effects and the effects of the plume and turbulence accompanying the passage of the Lipetsk meteoroid have been estimated. It has been shown that the passage of the celestial

Abstract—The propagation of solar cosmic rays (SCR) in the interplanetary medium is considered on the basis of the Fokker–Planck kinetic equation. It is known that the SCR distribution function averaged over a solar proton event contains valuable data on the scattering process for energetic charged particles by interplanetary magnetic fields. A steady-state solution for the kinetic equation in the

Abstract—From 2D-spectral observation data of a quiet region of the solar disk center in the Fe I λ 557.609 nm line, 3D hydrodynamic models of photospheric jets are built by solving the inverse radiative transfer problem. The obtained models describe thermodynamic parameters and the complete velocity field (vertical and horizontal). It is shown that the photospheric jets under consideration arise from

Abstract—The propagation of high-energy charged particles in the magnetic field, which is a superposition of the mean homogeneous magnetic field and magnetic inhomogenieties of various scales, is considered on the basis of the Fokker-Planck kinetic equation. The analytical expression for the cosmic ray distribution function corresponding to the instantaneous particle injection in the direction perpendicular

Abstract—This study aims at estimating some of the physical effects associated with the passage through the atmosphere and airburst of a meteoroid near Lipetsk (Russia) on June 21, 2018. The meteoroid’s initial kinetic energy was close to 11.7 TJ or 2.8 kt TNT. Approximately 10.4% or 1.22 TJ of the initial kinetic energy transformed into a flare. The meteoroid was found to be stony or, more specifically

Abstract—The importance of taking the SiO absorption in the infrared spectrum into account for spectral analysis of late-type stars is demonstrated. The lists of absorption lines of the fundamental SiO system calculated by the group of J. Tennison in the ExoMol project were used. The bands of isotopic molecules 28SiO, 29SiO, and 30SiO were identified in the spectrum of red giant HD 196610 (V*EU Del

Abstract—Additional arguments for the existence of a specific nongravitational effect (NGE) in the asteroid belt, which was discovered more than 10 years ago, are presented. Under the influence of this NGE, the semimajor axes of orbits of low-albedo asteroids increase gradually relative to the semimajor axes of orbits of asteroids with higher albedos. This is confirmed by the albedo–semimajor axis

Abstract—It has been concluded that, in the powerful magnetosphere of Jupiter, the subsolar point, which changes its position over the orbital period by an angle of approximately 26°, causes seasonal variations in the physical characteristics of the atmosphere. The significant eccentricity of the planetary orbit leads to the fact that the influx of energy to the atmosphere in the northern hemisphere

AbstractThe process of the rise and development of low-frequency instability of kinetic Alfven waves (KAW) and kinetic ion-acoustic waves (KIAW) in preflare solar plasma near the footpoints of magnetic loops, i.e., in the area that corresponds to the height of low-middle chromosphere, has been studied. The observational data obtained in the framework of international missions Hinode, SDO, and IRIS

AbstractTo overcome the difficulty in effective dissipation of currents in electromagnetic flare models associated with high gas-kinetic conductivity of the solar plasma, attention is given to the possibility of a local decrease in conductivity in the places of highly developed MHD turbulence near the neutral lines of photospheric magnetic configurations. The concept of redistribution of electrical

AbstractMicroturbulence, macroturbulence, thermal motion, and rotation contribute to the broadening of line profiles in stellar spectra. Reliable data on the velocity distribution of turbulent motions in stellar atmospheres are needed to interpret the spectra of solar-type stars unambiguously in exoplanetary research. Stellar spectra with a high resolution of 115 000 obtained with the HARPS spectrograph

AbstractThe variations in the spectral parameters of the sodium doublet Na I D line of the high-latitude supergiant 89 Her were investigated on the basis of the spectrograms obtained at the 2-m telescope of Shamakhy Astrophysical Observatory for 1975–2017. The research has shown that, in addition to shorter periodic changes, which were found earlier by various authors, there are also long-period changes

AbstractTo reveal and study magnetic features in the active region NOAA 11024, temporal changes in the profiles of the Stokes parameter V of photospheric lines Fe I λ 630.15 nm, Fe I λ 630.25 nm, Fe I λ 630.35 nm, and Ti I λ 630.38 nm were analyzed. Data of spectropolarimetric observations carried out with a high temporal and spatial resolution at the French-Italian solar telescope THEMIS (Tenerife

AbstractAp stars are chemically peculiar, main-sequence stars with atmospheres having an anomalous chemical composition (compared to the solar one). This abnormal chemical composition is thought to result from diffusion of chemical elements under the influence of radiation pressure and gravitational settling. Depending on the prevailing process, a chemical element either sinks and is accumulated in

AbstractTwo-dimensional spectra of the Sun (from the center to the limb of the disk) in wavelength ranges of λ = 532.0–532.8 and 539.1–539.9 nm were registered with the ATsU-5 telescope (the Russian abbreviation ATsU corresponds to the Astronomical Coelostat Mounting) of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine (MAO NASU) after replacing the regular main mirror

AbstractExamination results for specific features of variation of line-of-sight plasma velocities in different photosphere layers of the NOAA 11024 active region (AR) under the influence of two evolving Ellerman bombs (EB-1 and EB-2) are presented. Spectroscopic data with high spatial and temporal resolution were obtained with the French–Italian THEMIS solar telescope on July 4, 2009. The observation

AbstractThe acceleration of energetic particles and their propagation in magnetic fields of the solar wind and the Galaxy is a topical astrophysical problem. Cosmic rays (CR) affect communications and the operation of on-board spacecraft electronics and disturb the magnetosphere and the ionosphere of the Earth. The scattering of particles by magnetic-field irregularities is the primary mechanism governing

AbstractFrom October 7, 2012, to January 28, 2017 (GPS weeks 1709–1933) all products of the International GNSS Service (IGS)—precise ephemerides of GPS and GLONASS satellites, coordinates and velocities of permanent GNSS stations, etc.—were based on the IGb08 reference frame, the updated IGS realization of the release of the International Terrestrial Reference Frame (ITRF2008). Observations of GNSS

AbstractSolar wind is a set of flows with different parameters (the speed, the exponent of the spectrum of heterogeneities, the width, etc.). A bimodal character of the speed distribution of the solar wind was determined in spaceborne experiments. The measurements onboard the Ulysses spacecraft confirmed that the bimodal structure of solar wind continues to persist at relatively large distances from

AbstractThis study is dedicated to determining the values of the physical parameters of cloud particles in the deep layers of Saturn’s atmosphere using the data from remote measurements of the solar radiation field diffusely reflected by the giant planet. In the previous studies, using the effective optical depth method, from the spectral measurements of the geometric albedo of Saturn in 1993 in the

AbstractThe results of the spectral and photometric studies of two Be/X-ray binaries, 1H1936+541 and 1H2202+501, are presented. The spectral class of the optical component of the 1H1936+541 system was determined for the first time, and the spectral class of the optical component of the 1H2202+501 system was refined. According to the results, the optical components of the systems 1H1936+541 and 1H2202+501

Abstract—The correlations of the color indices of central galaxies (Mr < –20.7) and their faint neighboring galaxies (Mr < –20.7) using the sample based on the SDSS DR9 (N = 60 561) have been studied. The galaxy sample was limited by the red shift 0.02 < z ≤ 0.06 and absolute magnitude –24m < Mr < –19.4m. The “Random Forest” method of machine learning was used to determine the morphological type of