Vol 35, No 4 (2019)

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 to the regular magnetic field is obtained. The solution of the kinetic equation in the small angle approximation is applied for the case of particle emission along the mean magnetic field. It is shown that the spatial-temporal cosmic ray distribution depends substantially on the direction of particle injection. The evolution of the angular distribution of solar cosmic rays is analyzed on the basis of the derived solutions of the kinetic equation.

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, spectral class M6 III) taken from the IRTF spectra library. The relative abundance of silicon isotopes in the atmosphere of HD 196610 was estimated by modeling the bands of the first SiO overtone in the stellar spectrum. This abundance turned out to be close (within 3%) to the solar one. At the same time, the carbon isotope ratio ¹²C/¹³C = 6 ± 1 determined by modeling the isotopic components of the first overtone of CO bands suggests that HD 196610 is at an advanced stage of its evolution.

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, a chondrite, with a matter density of 3.3 t/m³. The celestial body moved at an angle of approximately 79° with respect to the horizon. The body’s initial mass equaled approximately 113 t, its initial speed was 14.4 km/s, and the initial diameter was 4 m. The altitude of the Lipetsk meteoroid’s explosion was close to 27 km, and the length of the explosion region equaled approximately 3.75 km. A comprehensive modeling of the processes initiated by the meteoroid’s passage through all geospheres has been performed. Mechanical, optical, and gas-dynamic effects associated with the Lipetsk meteoroid’s passage have been estimated. The primary release of energy (10¹³ J) is shown to occur at an altitude of approximately 25–27 km, where the rate of the mass loss approached 130–140 t/s and the deceleration was close to 21 km/s². In the vicinity of the meteoroid’s explosion, the meteoroid’s speed decreased by approximately 12%, and its mass decreased by 16%. The main parameters of shock wave have been estimated. The shock wave energy and power are equal to approximately 10 TJ and 0.8 TW, respectively. At the epicenter of the meteoroid’s explosion, the pressure at the shock front reached ≈140 Pa. This turns out to be insufficient for causing the destruction of buildings. The optical flare energy and power were equal to 1.22 TJ and 2–3 TW, respectively. The flare energy was 5–6 orders of magnitude less than that necessary for causing the ignition of materials and fires in the epicenter region. The relative disturbances in the air pressure at ionospheric altitudes above the explosion epicenter attained tens and even hundreds of percent.

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 is 21% greater, because the planet is at perihelion at the time close to the summer solstice for the northern hemisphere. This causes the asymmetry in the meridional distribution of the reflective properties of the visible cloud layer. The analysis of the observational data for 1960–2019 shows that the ratio A_J = B_N/B_S adequately describes the changes in the atmospheric processes on Jupiter, showing quasi-periodic variations in the reflective characteristics of the northern and southern temperate and tropical regions over the period of the orbital motion around the Sun (11.87 years). The change in Jupiter’s integral brightness in the V visual band indicates a more pronounced effect of the 22.1-year Hale magnetic cycle of solar activity. The results of the visible-light observations in 1960–1995 and 2012–2019 showed a synchronous delay of several years as a response to a 21% change in the irradiation of different hemispheres as the planet moves in orbit. In 1995–2012, a disagreement was observed between the dependence A_J, the solar activity index S_n, and the mode of the solar irradiation of Jupiter due to its orbital motion. After 2012, the course of the time dependence of these three parameters again became consistent, restoring the periodicity of the variations in the photometric characteristics of the northern and southern hemispheres of Jupiter.