Kinematics and Physics of Celestial Bodies最新文献

From May 17, 2020 to November 26, 2022 (GPS weeks 2106–2237) 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 IGb14 reference frame, the second IGS realization of the release of the International Terrestrial Reference Frame ITRF2014. 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 (MAO) NAS of Ukraine. The processing was carried out with the Bernese GNSS Software ver. 5.2 according to the requirements of the EUREF Permanent GNSS Network (EPN), that were relevant at that time. In total, observations on 344 GNSS stations, including 273 Ukrainian stations belonging to the following operators of GNSS networks: MAO NAS of Ukraine, StateGeoCadastre of Ukraine (UPN GNSS), PJSC System Solutions (System.NET), NU Lviv Polytechnic (GeoTerrace), Navigation and Geodetic Center (NGC.net), Kiev Institute of Land Relations (KyivPOS), Coordinate navigation maintenance system of Ukraine (NET.Spacecenter), E.P.S. LLC, UA–EUPOS/ZAKPOS, TNT TPI company (RTKHUB Network), and KMC LLC, were processed. The IGb14 reference frame was set by No-Net-Translation conditions on the coordinates of the EPN Class A stations from the EPN C2130 catalogue. As result, the station coordinates in the IGb14 reference frame and the zenith tropospheric delays for all stations were estimated. The mean repeatabilities for components of station coordinates for all weeks (the characteristics of the precision of the received daily and weekly solutions) are in the following ranges: for north component—from 0.62 to 1.35 mm (the average value is 0.98 mm), for east component—from 0.73 to 1.45 mm (the average value is 1.09 mm) with outliers of 2.39 and 1.81 mm for GPS weeks 2159 and 2168 respectively, for height component—from 2.52  to 6.36 mm (the average value is 3.89 mm).

Inertia is one of the most vivid and at the same time puzzling physical properties of bodies. As an equivalence between inertial and gravitational mass in general relativity, there is still no experimentally confirmed quantum mechanical description of inertia. There is great hope for such a description, as it could possibly elucidate cosmological anomalies and provide the missing link between relativistic theories and quantum mechanics. In this work, we refute the explanation of inertia by the concept of Modification of inertia resulting from a Hubble-scale Casimir effect (MiHsC) or Quantized Inertia (QI).

Comprehensive modeling studies of the thermal, turbulent, and plasma processes induced in all geospheres by the passage and explosion of the Kyiv meteoroid on April 19, 2023, were performed. Thermodynamic and plasma effects, as well as the effects and turbulence, accompanying the passage of the Kyiv meteoroid were estimated. It has been shown that the passage of the celestial body led to the formation of a gas-dust plume. The heated trail of the meteoroid cooled for several seconds. A simplified one-dimensional model of plume motion in the vertical direction is considered. The acceleration and speed of the plume are estimated. It has been shown that the initial acceleration of the plume initially reached a maximum value of 117 m/s² and lasted ~1 ms. Its speed increased from 0 to ~1 m/s, then gradually decreased to 0 m/s. At this speed, the height of the plume’s ascent hardly increased. The products of the explosion contained in the thermal, specks of dust and aerosols, further took part in the following three processes: a slow precipitation to the surface of the Earth, turbulent mixing with the ambient air, and transport by the predominant winds around the globe. The effect of turbulence in the trail has been shown to be well-pronounced, while the effect of magnetic turbulence has been shown to be absent. The following basic parameters of the plasma in the trail have been estimated: the height dependences of the electron densities per unit length and per unit volume, their relaxation times, the particle collision frequencies, the plasma specific conductivities, and the electron temperature relaxation time. At the initial moment, the linear and volume electron densities in the trail have been shown to be equal to approximately 10¹⁷–10²³ and 10¹⁷–10²² m^–3, respectively, and the plasma specific conductivity to be equal to ~10³ Ohm^–1 m^–1. The role of the dusty plasma component was insignificant.

The influence of the Earth’s rotation on the spectrum of low-frequency wave disturbances in an isothermal atmosphere is investigated. The system of equations for small linear disturbances is obtained in the “traditional” approximation and in the β-plane approximation, taking into account the frequency of rotation of the atmosphere. The found equations differ from the previously obtained ones in that the left parts of the equations depend only on time, whereas the right parts are expressed in terms of disturbed pressure. It is shown that, at zero perturbed pressure, taking into account the atmospheric rotation in the equations leads to the “splitting” of the obtained system into separate equations describing vertical and horizontal perturbations. Compact analytical solutions were obtained for both types of disturbances. It was established that vertical disturbances are realized in the form of Brunt–Väisälä waves, while horizontal are realized in the form of Rossby waves and inertial oscillations.

In this paper, we have investigated the effect of small perturbations in the Coriolis (ϕ) and centrifugal (ψ) forces in the Photogravitational magnetic binary problem including the effect of third body as variable mass. The objective of this work is to analyse the effect of ψ and other parameters (magnetic moments (λ) and radiation pressure (q)) on the existence and evolution of equilibrium points, basins of convergence (BoC), degree of unpredictability in BoC. In addition, to examine the effect of ϕ and ψ (in the presence of other parameters) on the stability of equilibrium points are also one of the aspect of this work. For different values of parameters, a total number of cases of non-collinear equilibrium points are 3, 5 and 7. The effect of various parameters on the evolution of equilibrium points are explained with the help of graphs. All non-collinear equilibrium points are found to be unstable for permissible range of parameters present in this model. The change in geometry of BoC’s is also shown and explained using graphs. The effect of ψ, q and λ on the degree of unpredictability in BoC’s is examined using the method of basin entropy. It is found that for the complete range of λ and q, the BoC’s are in fractal region. Also, for the values of ψ = 1.37, 1.38 and 1.40 to 1.44, the boundaries of BoC’s are in non-fractal region.

An actual problem today is the search for observed evidence of the existence of deep small-scale magnetic fields of the Sun. In this regard, the authors analyzed the theoretical criterion for separating the contributions to the solar surface magnetism of two qualitatively different mechanisms of a small-scale dynamo, the action of which is hidden in the depths of the solar convection zone (SCZ), proposed by Sokoloff and Khlystova [Astron. Nachr. 2010. 331. P. 82–87]. The first mechanism ensures the generation of small-scale magnetic fields due to the interaction of turbulent motions with the mean magnetic field (small-scale dynamo-1 of macroscopic MHD), while the second mechanism causes self-excitation of magnetic fluctuations due to turbulent pulsations of highly conductive plasma ( diffusive small-scale dynamo-2 of classical MHD). The essence of the proposed criterion is that deep small-scale magnetic fields can lead under certain conditions to violations of Hale’s and Joy’s laws of observed magnetism on the surface of the Sun. Statistical analysis of these disturbances allows one to identify the differences in the evolution of the observed manifestations of two sources of small-scale fields since the contribution of two deep dynamo mechanisms to surface magnetism varies with the phase of the solar cycle in different ways. Such an important feature is the behavior of the percentage of anti-Hail groups of sunspots (in relation to the total number of sunspots) during the cycles. In the case of small-scale dynamo-1, the percentage of anti-Hale groups is independent of cycle phase, whereas the percentage of anti-Hale groups associated with diffusive small-scale dynamo-2 should reach its maximum value at solar minima. Therefore, the variations of magnetic anomalies make it possible to separate the meager contributions of two small-scale dynamo mechanisms to surface magnetism. In this connection, the task of identifying the markers of a small-scale dynamo in the solar depths from observations becomes relevant. With this in mind, we conducted an analysis of literature data of statistical studies of long series of observed violations of Hale’s and Joy’s laws, which can be caused by the presence of deep small-scale magnetic fluctuations of various origins. In particular, it was demonstrated in the work of Sokoloff, Khlystova, and Abramenko [Mon. Notic. Roy. Astron. Soc. 2015. 451. P. 1522–1527] on the basis of processing the data of different catalogs for the period 1917–2004 that the percentage of anti-Hale groups of spots increases during the minima of solar cycles. This testifies to the operation of a diffusive small-scale turbulent dynamo-2 within the SCZ, the efficiency of which becomes noticeable near the minima of the cycles, when the global toroidal magnetic field weakens. As a result of the authors' analysis of six magnetic active regions observed near the minima of the 24th and 25th solar cycles, characteristic violations of Hale’s and Joy’

We present the results of an analysis of a homogeneous 15-year series of measurements of polarimetric standards obtained using the 2.6-m Shajn telescope of the Crimean Astrophysical Observatory Research Institute of the Ministry of Education and Science of Ukraine and an aperture polarimeter with fast full modulation. Out of the 98 standards of small and large linear polarization used, we do not recommend using 11 as standards for one reason or another.

This study is aimed at comprehensively analyzing and estimating the effects in gas dynamics, as well as mechanical and optical effects, from the Kyiv meteoroid that entered the terrestrial atmosphere and exploded over Bila Tserkva raion, Kyiv oblast (Ukraine). According to the International Meteor Organization (IMO), the apparent magnitude of the meteoroid was –18. According to our estimates, the luminous power was 215 GW with an effective duration of 2.4 ± 0.2 s, the total luminous energy was 25.2 ± 2.5 GJ, and the initial kinetic energy was 0.09 ± 0.01 kt of TNT or 375 ± 35 GJ. The initial mass of the cosmic body was estimated to be 0.89 ± 0.09 t, the volume was 0.250 ± 0.025 m³, and the size was 79 ± 3 cm. The initial velocity of the meteoroid reached 29 km/s. The inclination angle, i.e., the angle that the trajectory makes with the horizontal plane, was 32°. The explosion altitude equal to 38 km and the inclination angle equal to 32° give an estimate of 3.5 t/m³ for the material density, which is close to the rock density. The energy of the processes, the gas dynamics effects, and the mechanical and optical effects from the celestial body have been analyzed. The main release of energy associated with the deceleration of the fragments of the celestial body, which was defragmented under a dynamical pressure of approximately 2.5 MPa, took place in the region with a length of 2 km at an altitude of approximately 38 km. A quasi-continuous defragmentation is suggested to produce a mass distribution that follows a power law. The main parameters of the ballistic and explosive shock waves have been estimated. For the Mach number of 97, the radius of the ballistic shock wave is estimated to be approximately 77 m, and the fundamental period to be 0.7 s, which showed a dispersive increase from 3.7 to 11.5 s with the propagation path length increasing from 50 to 5000 km. The radii of cylindrical and spherical wavefront shock waves were approximately 0.28 and 0.34 km, and their fundamental periods were approximately 2.6 and 3.2 s, respectively. These periods increased from 9.5 to 30.0 s and from 11.1 to 35.1 s with an increase in the propagation path length from 50 to 5000 km. In the vicinity of the meteoroid’s explosion height, the relative excess pressure was a maximum. It decreased with a decrease in the altitude and increased with an increase in the altitude up to approximately 120–150 km, at which it attained values of approximately 6–7% and then further decreased down to a few percent. The absolute value of the excess pressure is estimated to be near the altitude of the explosion; subsequently it decreased with a decrease in the altitude down to 20–25 km and then increased further again. At the epicenter of the explosion, it is estimated to be approximately 94 Pa for the cylindrical wavefront and approximately 99 Pa for the spherical wavefront, which is not enough to damage objects on the ground. The excess pressure decreased

The Tonga volcano is among the five most powerful volcanoes in the world. The explosion of the Tonga volcano on January 15, 2022, was unique. It has led to disturbances in the lithosphere, World Ocean, atmosphere, ionosphere, magnetosphere, and all geophysical fields. A number of studies have been devoted to the disturbance of the Earth’s magnetic field. The transport of magnetic field disturbances by atmospheric gravity waves and tsunamis, disturbances in magnetically conjugated regions due to acoustic resonance, the effect on the equatorial electrojet, etc., have been studied. This is far from the end of the variety of magnetic effects of the Tonga volcano. This study is aimed at describing the results of the analysis of global bay disturbances in the geomagnetic field observed after the Tonga volcano explosion on January 15, 2022. The results of measuring the temporal variations in the level of the X, Y, and Z components by the INTERMAGNET world network of stations are used as initial data. The analysis of the magnetic data is preceded by an analysis of space weather conditions. A preliminary analysis of temporal variations in the level of the X-, Y-, and Z-components indicates that these variations on the reference days are smoother than on January 15, 2022. An analysis of the temporal variations in the level of the X-, Y-, and Z-components of the geomagnetic field and a statistical analysis of the disturbance parameters have shown the following. Bay disturbances of all components of the geomagnetic field are observed with a time delay that varies depending on the distance to the volcano from several tens of minutes to 100–200 min. The magnitude of the effect varies from approximately 10 to approximately 60 nT. The largest disturbances occur in the Y component. The delay time and duration of disturbances increase with an increase in the distance from the volcano, while their amplitude, on the contrary, decreases. The speed of propagation of bay disturbances is close to the speed of the blast wave. Bay disturbances are weakly expressed or completely absent on the night side of the planet. It is substantiated that bay disturbances are closely related to the occurrence of an ionospheric hole under the action of a blast wave from the volcano. The results of estimates of bay disturbances are in good agreement with the observation results.

We present the results of the study of the magnetic field in the active prominence on July 24, 1999 at 07:00 UT, using the observational material obtained on the Echelle spectrograph of the horizontal solar telescope of the Astronomical Observatory of Taras Shevchenko Kyiv National University. Our analysis is based on the study of I ± V profiles of the Hα line, which were related to heights in the range of 11–20 Mm. It was found that the bisectors of the I ± V profiles are non-parallel to each other in majority of places of this prominence. This indicates the inhomogeneity of the magnetic field: with a uniform magnetic field, the named bisectors should be parallel. Moreover, the maximum splitting of bisectors is observed not only in the core of the line (which was found earlier by other authors), but also in its far wings, at distances of 1.5–2.5 Å from the line center. The specified maximum of splitting corresponds to magnetic field of about 3000 G, but this value should be considered only as a lower estimate of the true local magnetic fields. In particular, the second maximum of bisector splitting may indicate that the actual value of Zeeman splitting in small-scale structures with a small filling factor reaches the above value of 1.5–2.5 Å which corresponds to the field strength of almost 100 kG. From our study it follows that evidences on such extremely magnetic fields may not actually be a rare phenomenon, but a rather common one, which, however, can be recorded only under certain favorable observational conditions.