Volume 35, Nº 1 (2019)

The 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 the CR propagation in the interplanetary medium. If the scattering of energetic particles in the interplanetary medium is relatively inefficient (i.e., the mean free path is comparable to the heliocentric distance), a kinetic equation should be used to characterize the CR propagation. The Fokker–Planck kinetic equation is used to analyze the propagation of charged energetic particles in a magnetic field represented as a superposition of a mean uniform field and magnetic inhomogeneities of various scales. This kinetic equation corresponds to multiple small-angle scattering, and its collision integral characterizes particle diffusion in the momentum space. A system of differential equations for the spherical harmonics of the CR distribution function is obtained based on the kinetic equation. The CR transport equations are derived and solved. The evolution of the CR distribution function under anisotropic scattering of particles by magnetic-field fluctuations is examined. It is demonstrated that the angular distribution function of particles depends to a considerable extent on the degree of their scattering anisotropy. The temporal dependence of the CR distribution function is analyzed, and the parameter characterizing the scattering anisotropy is estimated.

This 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 wavelength range of 300–1000 nm, a pressure dependence of the aerosol scattering component of the optical depth, i.e., a change in its value with altitude in the atmosphere, was obtained. The analysis of the initial data was performed in the long-wave part of the spectrum in the methane absorption lines of different levels of absorption with the centers at wavelengths of λ = 619, 727, 842, 864, and 887 nm. At certain altitude levels in the deep layers of the atmosphere of the giant planet, the indicated dependence shows the features that possibly reflect changes in the physical characteristics of aerosol. Therefore, the aim of this work was to determine the possible values of the physical parameters of aerosol particles in the deep layers of Saturn’s atmosphere at altitudinal levels with the features noted above. As a result, an increase in the effective radius of cloud particles was observed in the transition from the outer to the deeper layers of the atmosphere: from 1.4 μm in the upper part of atmosphere to 1.83 μm in the altitudinal region with a pressure of 1.0–1.25 bar and up to 2.2–2.4 μm in the region with a pressure of 1.5–2.0 bar. In the latter segment, a decrease by 3.5% was revealed in the real part of the refractive index of aerosol particles. A possible reason for this decrease is the change in the phase state of aerosol particles in the lower and warmer atmospheric layers of Saturn due to the presence of ammonium hydroxide in their composition at a sufficient high concentration.

The 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 are Be stars of the spectral types B1Ve and B3Ve, respectively. These findings, as well as the well-known spectral type distribution of Be stars, can testify to the fact that the object 1H1936+541 belongs to X-ray binary systems. At the same time, taking into account the fact that a very small number of Be/X-ray binaries of the spectral type B3 is known so far, the object 1H2202+501 cannot unambiguously be classified as a Be/X-ray binary. The rotational speeds of the main components of these systems are 246 ± 11 km/s for 1H1936+541 and 111 ± 8 km/s for1H2202+501; the range of the tilt angles of their rotation axes is within 49°–82° and 21°–28°, respectively. Additionally, using the B and V band photometric observations and spectral classes obtained, the interstellar extinction values E(В – V), as well as the distances to the objects, were estimated. In particular, for 1H2202+501, the value of E(В – V) is 0.36 ± 0.03^m, and the distance r ranges from 0.8 to 1.6 kpc. For the 1H1936+541 system, the following values were obtained: E(В – V) = 0.23 ± 0.03^m and r = 2.1–3.6 kpc. The comparison of the distances to the objects with the data from the GAIA DR2 catalog (http://gea.esac.esa.int/archive/) revealed the coincidence of the corresponding values within the limits of errors.

From 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 satellites at permanent stations located in Ukraine and in Eastern Europe for this period were processed in the GNSS Data Analysis Centre of the Main Astronomical Observatory of the National Academy of Sciences of Ukraine. The processing was carried out with Bernese GNSS Software ver. 5.2 according to the requirements of the European Permanent GNSS Network (EPN) that were valid at that time. In total, observations on 232 GNSS stations, including 201 Ukrainian stations belonging to the following operators of GNSS networks were processed: MAO NAS of Ukraine, Research Institute of Geodesy and Cartography, NU Lviv Polytechnic (GeoTerrace), PJSC System Solutions (System.NET), TNT TPI company (TNT TPI GNSS Network), Navigation Geodetic Center Ltd. (NGC.net), UA-EUPOS/ZAKPOS, Europromservice Ltd. (EPS), Coordinate Navigation Maintenance System of Ukraine (CNMSU), and Kharkiv National University of Radio Electronics. The IGb08 reference frame was set by No-Net-Translation conditions on the coordinates of the IGS Reference Frame stations. As result, the stations’ coordinates in the IGb08 reference frame and the zenith tropospheric delays for all stations were estimated. The mean repeatabilities for components of stations’ coordinates for all weeks (the characteristics of the precision of the received daily and weekly solutions) are in the following ranges: for north and east components—from 0.5 mm to 1.6 mm (average values are 0.99 mm and 1.01 mm respectively), for hight component—from 2.2 mm to 5.4 mm (average value is 3.75 mm) with an outlier of 6.91 mm for GPS week 1759.