bluuebunny/crossref_metadata_2025 huggingface dataset:
Oceanic Crust Formation in the Mid-Atlantic Ridge Segment between Azores and Icelandic Plumes: Results of Geological and Petrogeochemical Studies
Authors: Skolotnev S. G. , Peyve A. A. , Sokolov S. Yu. , Dokashenko S. A. , Dobrolyubov V. N. , Okina O. I. , Ermolaev B. V. , Dobrolyubova K. O.
Published: April 2024

The structure of the ocean floor and the composition of basalts and dolerites of the MAR segment between the Maxwell and Charlie Gibbs FZs (North Atlantic) were studied based on the data of the 53rd cruise of the R/V “Akademik Nikolaj Strakhov”. It was found that in this segment, along the spreading axis, areas of greater and lesser magmatic productivity alternate, which correspond to higher and lower bottom relief. In areas of high relief, spreading cells form in the axial zone, and rises of various nature dominate in the ridge zone: from tectonic to volcanic. In areas of low relief, the rift valley consists of deep rift basins, and low ridges are developed on the flanks, separated by wide depressions. Oceanic tholeites N, T and E-MORB are distinguished among the studied volcanites. The first of them are ubiquitous and were melted from mainly depleted mantle (source DM). Basalts and dolerites of E-MORB are found in areas of high relief. Their mantle substrate is formed by a mixture of DM and EM-2 material with the subordinate role of HIMU. T-MORB volcanites are mainly localized on large volcanic rises in the southern part of the studied MAR segment and were melted from a substrate formed by a mixture of DM and HIMU material with the subordinate role of EM-2. Two types of mantle inhomogeneities involved in melting are reconstructed: passive and active. The former are represented by blocks of the transformed continental lithosphere that are similar in composition to the EM-2 mantle source. Active inhomogeneities associate with the uplift near Maxwell FZ of the microplume of the enriched mantle with a composition close to HIMU and with its subaxial flow in the north direction up to the Charlie Gibbs FZ.
Ediacaran and Cambrian Volcanogenic and Sedimentary Complexes of Southern Ulutau (Central Kazakhstan): Structure, Substantiation of Age and Setting of Formation
Authors: Tretyakov A. A. , Degtyarev K. E. , Kanygina N. A. , Zhuravlev A. N. , Skuzovatov S. Yu.
Published: April 2024

The article presents the results of studying and substantiating the age of the Ediacaran volcanogenic-sedimentary and Cambrian sedimentary strata isolated for the first time within the southern part of the Ulutau terrane (Southern Ulutau) in the west of Central Kazakhstan. Age Estimates (SHRIMP II) obtained 594 ± 3, 594 ± 5, 600 ± 2 Ma for effusive and tufogenic rocks, as well as their isotope-geochemical characteristics, are the first evidence of the manifestation of Ediacaran suprasubduction magmatism in the paleozoics of Kazakhstan and the Northern Tien Shan. The data obtained indicate the participation of the Ulutau terrane at the end of the Precambrian in the structure of the volcanic-plutonic belt, fragments of which are also Neoproterozoic blocks within Southwestern Kazakhstan (the Zeltava and Chui‒Kendyktas terranes) of the Southern Tien Shan and the Karakum‒Tajik terrane. The formation of the Ediacaran suprasubduction belt may be a continuation of the evolution of the Neoproterozoic active continental margin that arose in the Tonian period on the northwestern margin of the supercontinent Rodinia.
Influence of Mid-Oceanic Ridges on Seismicity of Novaya Zemlya Archipelago
Authors: Antonovskaya G. N. , Konechnaya Ya. V. , Basakina I. M.
Published: April 2024

The influence of the mid-oceanic ridges (MOR), including the Gakkel Ridge and the geological system Knipovich Ridge–Trough Lena, on the seismicity of the Novaya Zemlya archipelago area for 1980‒2022 is considered. For each geological element under consideration, we compiled seismic catalogs with a single unified magnitude mbISC for an equivalent comparison of information, and the annual seismic energy was calculated, and graphs of its distribution by year were constructed. We performed analytical modeling based on the Elsasser model describing the process of local stress transfer in a rigid elastic lithosphere underlain by a viscous asthenosphere, and made quantitative calculations of the disturbance propagations from MOR. The time intervals through which disturbances from MOR reach the Novaya Zemlya archipelago are 1‒2 years for the geological system Knipovich Ridge–Trough Lena and 3‒5 years for the Gakkel Ridge. The maximum joint contribution to the level of seismic activity of various geological and tectonic structures of the MOR can reach 40‒60% of the applied disturbances values, which is a sufficient condition for the influence on seismicity of the Novaya Zemlya orogen. The most geodynamical active structures and zones of concentration of tectonic stresses are identified.
Model Variations of the Crust Thickness of Mars and Venus Using the Love Numbers Method
Authors: Batov A. V. , Menshchikova T. I. , Gudkova T. V.
Published: April 2024

Based on topography and gravitational field data, model variations in the crust thickness of Mars and Venus were calculated using the Love numbers method. The method takes into account the adjustment of the planetary interior to loads on the surface and in the interior. Numerical modeling was carried out using the expansion in spherical harmonics of the topography and gravitational field data up to the 90th degree and order for Mars and up to the 70th degree and order for Venus. The topography of the crust–mantle boundary suggests partial Airy isostatic compensation. The model of the Martian crust is consistent with the interval of crustal thickness values under the site of the InSight station in the southwestern part of Elysium Planitia obtained from the results of a seismic experiment. The comparison with the available global models of the crust of Mars and Venus was carried out.
Comet 2I/Borisov in Comparison with Comets of the Solar System
Authors: Dorofeeva V. A. , Borisov G. V. , Shustov B. M.
Published: April 2024

The brief review summarizes data on the chemical and mineral composition, as well as on the phys ical properties, of the first extrasolar comet 2I/Borisov, obtained from observations that were carried out from September 2019 to the end of March 2020. It is noted that the qualitative chemical composition of the volatile and mineral components comet 2I/Borisov is similar to the composition of comets in the Solar System, but there are differences that indicate the specific conditions for the formation of its nucleus in a circumstellar gas and dust disk. Different release rates of CO and H2O molecules in the vicinity of perihelion indicate the pos sible heterogeneity of the comet’s nucleus, which was formed from more homogeneous ice blocks, but differ ing in composition. These constituent blocks could have formed over a wide range of radial distances: from the snow line of H2O to the CO snow line. Their accumulation in the comet’s nucleus indicates large-scale mixing of protocometary bodies in the circumstellar disk. No spectra of finely crystalline magnesium silicates were found in cometary coma of 2I/Borisov, which can be interpreted as the absence of a significant amount of gas and dust transfer from the inner hot regions of the disk to the outside, into the zone of formation of protocometary bodies.
Contaminants in the Lunar Regolith
Authors: Mokhov A. V. , Gornostaeva T. A. , Rybchuk A. P. , Kartashov P. M.
Published: April 2024

The lunar regolith delivered to Earth in the 1970s by the Soviet automatic stations Luna-16, -20, and -24, despite the small amount of material, is of great value for science and requires careful study. How ever, since soil samples have gone quite a long way from the moment of extraction to direct examination, there is a danger of possible contamination of the samples with foreign material, both man-made and terrestrial natural minerals. The probability of contamination of the finest fraction of regolith, the particle size of which is less than 100 microns, is especially high, since their detection is possible only by electron microscopy. Using the methods of analytical scanning electron microscopy in regolith samples, contaminant phases that con taminated the original preparations were found, and the sources of these artifacts were shown. The examples of contamination of regolith samples given in this paper and the methods for their identification will make it possible in the future to more accurately diagnose the phases of lunar origin.
Selected Problems of Classical and Modern Celestial Mechanics and Stellar Dynamics: I–Classical Results
Authors: Shaidulin V. Sh. , Shevchenko I. I. , Mel’nikov A. V. , Titov V. B. , Baluev R. V. , Veselova A. V. , Krivov A. V. , Mikryukov D. V. , Milanov D. V. , Mülläri A. A. , Nikiforov I. I. , Pit’ev N. P. , Polyakhova E. N. , Sokolov L. L.
Published: April 2024

A review is given, in the modern context of applications, of the major important scientific results obtained by scientists and graduates of St. Petersburg State University in the field of celestial mechanics and stellar dynamics. The following topics are discussed: the Antonov laws of stellar dynamics, Abalakin–Batrakov libration points, Kholshevnikov metrics, Agekyan–Anosova homological region, Orlov metastable triple systems, Ogorodnikoff–Milne models, Ossipkov–Merritt models, estimation and calculation of the MOID parameter, photogravitational celestial mechanics and solar sail, problems of asteroid–comet hazard, dust complexes in the Solar System, rotational dynamics of planetary satellites, circumbinary dynamics, and methods for the discovery and determination of orbits of exoplanets. The first part of the review presents the classical results.
Electromagnetic Phenomena Accompanying the Passage of an Iron Meteorite Through the Earth’s Atmosphere
Authors: Filonenko A. D.
Published: April 2024

Based on observational facts, the author proposes a model for the formation of an electric charge in iron meteorites in the lower layers of the atmosphere through photoelectron emission when exposed to high-temperature plasma radiation on its surface. It is shown that at high Mach numbers, the explosive destruction of an iron meteorite can be caused not only by inertial, but also by electrostatic forces. The sub sequent charging of the fragments greatly increases their total charge, and the movement with acceleration causes electromagnetic radiation in the low frequency range. The electrostatic and electromagnetic fields accompanying the movement of meteoroids in the atmosphere can be the cause of the observed effects on the Earth’s surface, i.e., radio interference, electric shock to a person, and St. Elmo’s fire, among others.
Spatial and Genetic Relations of Coronae, Lobate Plains, and Rift Zones of Venus
Authors: Guseva E. N. , Ivanov M. A.
Published: April 2024

Based on the photogeological and stratigraphic analysis of Venusian coronae, we have found that (1) late manifestations of volcanic activity on Venus, lobate plains, are weakly related to the formation of coronae. The small number of coronae–sources of lobate plains (~17% of the total population of coronae) indicates that the volcanic activity of the coronae ceased mainly in the pre-Atlian time. Thus, the coronae associated with manifestations of late volcanism in the form of lobate plains are either long-lived volcano tectonic complexes or structures of the final phases of volcanic activity; their locations mark the regions of long-term volcanism; (2) the small number of coronae formed by rift structures (~14% of the total popula tion) indicates that rifting in the Atlian period did not lead to mass formation of coronae. The majority of Venusian coronae was probably formed in the Fortunian–Guineverian periods of the geological history of Venus. A sharp decrease in the number of coronae formed in the Atlian period may be associated with an increase in the thickness of the lithosphere and an increase in its role as a rheological barrier.
Estimation of Ejecta Thickness from Impact Craters in the South Polar Region of the Moon
Authors: Krasilnikov A. S. , Krasilnikov S. S. , Ivanov M. A. , Head J. W.
Published: April 2024

The paper presents the results of model calculations of impact craters ejecta thickness variations in the south polar region of the Moon from the south pole to 70° S for craters of Nectarian, Imbrian, Eratos thenian, and Copernican ages. This work does not consider pre-Nectarian craters since younger deposits often hide the boundaries of their ejecta. Housen, Sharpton and Fassett models were chosen to estimate the power. The first was used for craters larger than 45 km in diameter, the second for smaller craters (from 3 to 45 km), and the third for the Mare Orientale basin. During estimation, the mixing factor of ejecta with the underlying regolith (factor μ) was considered. As a result, maps of ejecta thicknesses were produced for the Moon’s south polar region. They provide an opportunity for quantitative estimation of the various aged impact events’ contribution to the formation of polar regolith and, accordingly, to determine the dominant source (sources) of material in a particular area, not least in the proposed landing sites.
On the Prospects for Estimating the Properties of Particles in an Active Asteroid Exosphere by Features in the UV and Visible Reflectance Spectra
Authors: Petrova E. V. , Busarev V. V.
Published: April 2024

The reflectance spectra of active asteroids (AAs) measured in the visible and near-UV ranges exhibit unusual features, which are apparently caused by the light scattering in an exosphere formed under active processes on an asteroid. To estimate the prospects for a quantitative interpretation of these features, we numerically simulated reflectance spectra of an AA enveloped by an exosphere composed of aggregate submicron particles of various composition and morphology, as well as homogeneous submicron particles. We assumed that the sizes of aggregates’ constituents correspond to those of grains in agglomerates of come tary and interplanetary dust. It has been shown that the scattering on aggregates of submicron grains produces interference features at wavelengths shorter than 0.6 μm, and the positions of these features are determined by both the sizes of these grains (rather than the aggregates themselves) and the real part of their refractive index. The structure of an aggregate and variations (up to ±20%) in the sizes of constituents weakly influence the position of these features. The shape of the spectrum at longer wavelengths also depends on the sizes of grains in the aggregates and serve as an additional criterion for estimating this parameter. Calculations per formed for aggregate particles absorbing in a short-wavelength range (which is typical of many materials that one may expect to find on AAs) show that the absorption significantly weakens the interference details appeared in this range. Hence, the attempts to detect strongly absorbing particles in the exosphere and to esti mate their properties by these spectral features cannot yield reliable results, as opposed to the simulations for weakly absorbing particles. The presence of homogeneous weakly absorbing submicron particles in the exo sphere of an AA results in a steady growth of the intensity at wavelengths shorter than 0.4−0.5 μm. Spectral measurements at the wavelengths shorter than 0.35 μm may help to estimate more reliably the properties of weakly absorbing particles, both aggregate and homogeneous, in the exospheres of AAs.
Selected Problems of Classical and Modern Celestial Mechanics and Stellar Dynamics: II–Modern Studies
Authors: Shevchenko I. I. , Melnikov A. V. , Titov V. B. , Baluev R. V. , Veselova A. V. , Krivov A. V. , Mikryukov D. V. , Milanov D. V. , Mülläri A. A. , Nikiforov I. I. , Pit’ev N. P. , Polyakhova E. N. , Sokolov L. L. , Shaidulin V. Sh.
Published: April 2024

A review is given, in the modern context of applications, of the major important scientific results obtained by the scientists and graduates of St. Petersburg State University in the field of celestial mechanics and stellar dynamics. The second part of the review covers the following topics: estimates and calculation of the MOID parameter, problems of asteroid–comet hazard, dust complexes in the Solar System, rotational dynamics of planetary satellites, circumbinary dynamics, and methods for the discovery and determination of orbits of exoplanets.
Estimating the Asteroid’s Impact Risk under Significant Nonlinearity in the Orbit Determination Problem
Authors: Baturin A. P.
Published: April 2024

A method has been developed for estimating the probability of an asteroid impact on the Earth. The method is based on the detection of impact orbit tubes in the initial confidence region, taking into account the nonlinearity in the problem of orbit determination. The method consists in sequential iteration of level surfaces of the minimized function and conditionally minimizing the distance from the asteroid to the Earth on them in some considered approach of the asteroid to the Earth. An approximate method has been developed for calculating the confidence level at any point in the initial region with a noticeable nonlinearity in the orbit determination problem. The impact risk is estimated by applying this method to the identified tube of impact orbits. The method has been tested for a number of potentially dangerous asteroids in their expected approaches to Earth.
Stable Orbits in the Feeding Zone of the Planet Proxima Centauri c
Authors: Ipatov S. I.
Published: April 2024

Estimates of the size of the feeding zone of the planet Proxima Centauri c have been made at initial orbital eccentricities of planetesimals equal to 0.02 or 0.15. The research is based on the results of modeling of the evolution of planetesimals’ orbits under the influence of the star and planets Proxima Centauri c and b. The considered time interval reached a billion years. It was found that after the accumulation of the planet Proxima Centauri c some planetesimals may have continued to move in stable elliptical orbits within its feeding zone, largely cleared of planetesimals. Usually such planetesimals can move in some resonances with the planet (Proxima Centauri c), for example, in the resonances 1 : 1 (as Jupiter Trojans), 5 : 4 and 3 : 4 and usually have small eccentricities. Some planetesimals that moved for a long time (1–2 million years) along chaotic orbits fell into the resonances 5 : 2 and 3 : 10 with the planet Proxima Centauri c and moved in them for at least tens of millions of years.
Secular Orbital Dynamics of Exoplanet Satellite Candidates
Authors: Melnikov A. V.
Published: April 2024

The stability of the secular orbital dynamics of a number of potentially existing satellites of exoplanets has been analyzed. The secular dynamics of possible satellites (“exomoons”) of the planets KOI-268.01, Kepler-1000b, and Kepler-1442b have been found to be stable. The possible values of the exomoon orbital parameters for these systems have been estimated. The dynamics of the satellites discovered around the planets Kepler-1625b and Kepler-1708b from the analysis of observations are considered. It has been found that the semimajor axis of the orbit of the moon of the planet Kepler-1625b can range from 5 to 25 planetary radii. It has been shown that the solution available for the satellites of the planet Kepler-1708b (Kipping et al., 2022) corresponds to a stable orbit of the satellites.
Estimation of the Neutron Component of the Radiation Background in the Gale Crater on Mars
Authors: Mitrofanov I. G. , Litvak M. L. , Sanin A. B. , Semkova I. V. , Dachevb Ts. P.
Published: April 2024

The paper presents the results of the analysis of the neutron component of the radiation background on Mars in the Gale crater, where the NASA Curiosity rover conducts its research. Numerical estimates have shown that the effective dose rate for neutrons at the maximum flux of galactic cosmic rays varies along the rover path by 20% in the range of 92–108 μSv/day. This variation is mainly driven by the variable content of subsurface water, which ranges from 0.5 to 5% mass fraction along the rover path. The estimates obtained are comparable with the measurements of the RAD radiation dosimeter. The comparison with doses from charged particles shows that the contribution of the neutron component on the surface of Mars to the total dose with no radiation protection is 10%, which should be taken into account when planning manned missions to Mars.
O2 (а1Δg) Airglow at 1.27 μM and upper Mesosphere Dynamics on the Night Side of Venus
Authors: Shakun A. V. , Zasova L. V. , Gorinov D. A. , Khatuntsev I. V. , Ignatiev N. I. , Patsaeva M. V. , Turin A. V.
Published: April 2024

This research studies the O2 (a1 Δg) nightglow distribution in 1.27 μm to understand the dynamics of the atmosphere of Venus. Several factors were considered in the retrieval process, such as thermal emission of the lower atmosphere, reflection by the clouds. Results show deviation from SS-AS circulation mode: the area where horizontal flows from the dayside converge and where oxygen recombines and emits shifts from the midnight to 22–23 hours local time. This shift is caused by solar-induced thermal tide on Venus nightside. Some conclusions about the upper mesosphere dynamics are also presented.
Fall to Earth of Fragments of Destroyed Asteroid
Authors: Svetsov V. V.
Published: April 2024

The effect of the destruction of asteroids in orbits as they approach the Earth, and the consequences of their impacts, have been estimated. The areas affected by a shock wave, a seismic wave, and radiation upon impact of stony asteroids on land or upon entry into the atmosphere over land at a speed of 20 km/s are determined for a range of their sizes of 20–500 m. It has been found that arbitrary destruction of an asteroid near the Earth can lead to an increase in the total area affected by shock waves and thermal radiation during impacts of individual fragments. In the general case, reduction of damage after the destruction of asteroids with diameters of 150–500 m can be achieved if the bulk of the fragments are bodies with dimensions of less than 20–30 m, which do not pose a catastrophic danger.
New Spectrometer ULTIMAN for Space Plasma Research
Authors: Vaisberg O. L. , Shuvalov S. D.
Published: April 2024

Measurements of ion velocity distributions are one of basic goals of space plasma studies. There is variety of ion and electron spectrometers (see, for example, Wüest et al., 2007; Young et al., 2007; Zurbuchen and Gershman, 2016; Vaisberg et al., 2016). The most commonly used ion spectrometer is the top-hat analyzer (Carlson et al., 1983) consisting of a toroidal electrostatic analyzer, an electrostatic scanner, and a timeof-flight section with thin foil as a start element and ion preacceleration. We describe a new energy-mass analyzer with an electrostatic scanner providing a hemispheric field of view with small aberration, a toroidal electrostatic analyzer, and a time-of-flight synchronizer with a simple gate. It provides desirable hemisphere scanning, wide energy range, and reasonable mass resolution to meet most space exploration challenges. It can provide detailed measurements of the ion velocity distribution of ion species without significant gaps to obtain the structure of the hot plasma flow. With simple electrooptics elements this analyzer can be easily modified for many plasma research purposes.
Ultralow Frequency Resonators: on the 80th Anniversary of the Discovery of Alfvén Waves
Authors: Guglielmi A. V. , Klain B. I. , Potapov A. S.
Published: April 2024

The concept of Alfvén waves, introduced into science 80 years ago, played an important role in the formation and development of cosmic electrodynamics. Alfvén waves differ in that at each point in space the group velocity vector and the vector of the external magnetic field are collinear to each other, due to which the waves can carry momentum, energy, and information over long distances. In memory of the outstanding event, we briefly describe two Alfvén resonators, one of which is located high above the Earth, in the radiation belt, and the second, in the ionospheric layers. Both resonators have a discrete spectrum in the upper part of the range of ultralow frequency oscillations of natural origin (approximately from 0.2 Hz to 7 Hz). The close connection between the concept of Alfvén waves and the current problems of the electrodynamics of geophysical media is especially emphasized.
ExoMars-2022 Mission ODS Instrument: Modeling and Ground Field Measurements
Authors: Khorkin V. S. , Fedorova A. A. , Dobrolenskiy Yu. S. , Korablev O. I. , Vyazovetskiy N. A. , Dzyuban I. A. , Sapgir A. G. , Titov A. Yu. , Toledo D. , Pommereau J.-P. , Rannou P.
Published: April 2024

The paper presents the results of modeling and ground-based field measurements of the ODS (Optical Depth Sensor) instrument, designed to study aerosol in the Martian atmosphere through daily measurements of illumination on the planet’s surface. The device was part of the meteo suite located on the landing platform of the ExoMars-2022 mission. The article presents the structure of the instrument, its optical design and the spectral characteristics of two channels. The main elements of the model for calculating the radiation flux measured by the instrument are described depending on the structure of the atmosphere, the aerosol suspended in it, and the daily motion of the Sun. The calculations were carried out in the approximation of a pseudospherical atmosphere, taking into account the multiple scattering of radiation. Using the created model adapted for the Earth’s atmosphere, the ODS signal was simulated for two series of ground-based field measurements at different latitudes. The measured daily dependences in comparison with the simulation results make it possible to determine the optical depth with an accuracy of 0.1.
Accelerometers of the Meteorological Complex for the Study of the Upper Atmosphere of Mars
Authors: Lipatov A. N. , Ekonomov A. P. , Makarov V. S. , Lesnykh V. A. , Goretov V. A. , Zakharkin G. V. , Zaitsev M. A. , Khlyustova L. I. , Antonenko S. A.
Published: April 2024

The accelerometers and the angular velocity sensor, which are part of the meteorological complex of the ExoMars-2022 landing platform (LP), are designed to measure the acceleration during the deceleration of the lander in the Martian atmosphere. Based on the data, the main parameters of the Martian atmosphere are calculated: density, pressure, and temperature. After landing, the sensors are used to determine the acceleration on the surface and vibration effects on the lander of various nature. The sensors are activated prior to entry into the atmosphere and operate during the entire descent until landing. After landing, a long-term monitoring is carried out to identify vibration effects from the atmosphere and the surface. In the paper we consider the scientific problems solved by the sensors, describe the measurement program and consider in detail the design of the sensors and their characteristics.
LIDAR for Investigation of the Martian Atmosphere from the Surface
Authors: Lipatov A. N. , Lyash A. N. , Ekonomov A. P. , Makarov V. S. , Lesnykh V. A. , Goretov V. A. , Zakharkin G. V. , Khlyustova L. I. , Antonenko S. A. , Rodionov D. S. , Korablev O. I.
Published: April 2024

The lidar device as part of the meteorological complex of the ExoMars-2022 landing platform is designed to study Martian aerosol, the planetary boundary layer, and small-scale atmospheric turbulence. A miniature lidar based on a pulsed semiconductor laser and an avalanche photodiode in the photon counting mode will make it possible to obtain aerosol backscattering profiles along a vertical path from 10 to 1500 m during the day and from 15 to 10000 m at night. In the passive mode, the sky brightness is measured in a narrow spectral range and in a narrow solid angle with a frequency of up to hundreds of hertz. The measured fluctuations can provide information about the turbulence of the daytime atmosphere and its relation to dust activity. In the paper we considered the scientific tasks of the experiment, the program of measurements on the surface of Mars and described in detail the components of the equipment and the features of their work.
Current Knowledge of Objects Approaching the Earth
Authors: Kokhirova G. I. , Babadzhanov P. B.
Published: April 2024

Modern ideas about objects approaching the Earth are discussed. This population includes near-Earth asteroids (NEAs), including potentially hazardous asteroids, short-period comets, meteoroid streams, and large sporadic meteoroids. An overview is given of the currently available information on the dynamic and physical properties of NEAs and comets. Almost 5% of the currently known NEAs are extinct cometary nuclei or their fragments. Being outwardly similar with true asteroids, they differ markedly in their dynamic and physical properties. In order to distinguish between these groups of objects, it is necessary to study both their dynamic and physical parameters. Some of the known meteoroid streams are shown to contain, along with the countless small meteoroids, also large extinct fragments of cometary nuclei, which are classified as NEAs. A meteoroid stream and such bodies belonging to it form together an asteroid–meteoroid complex. Observational and theoretical data are presented to confirm the modern understanding of near-Earth objects.
Influence of Planetary Encounters on the Magnitude of the Yarkovsky Effect in Asteroid Dynamics
Authors: Martyusheva A. A. , Melnikov A. V.
Published: April 2024

The influence of the solar radiation pressure and the Yarkovsky effect on the long-term orbital dynamics is estimated for a number of asteroids experiencing successive planetary encounters. The variation in the asteroid’s proper rotation period due to its approach to the planet and its effect on the asteroid’s further orbital dynamics through the Yarkovsky effect is considered. It is shown that close planetary encounters of small asteroids (tens of meters in diameter) with short rotation period (less than 10 h), which change the asteroid’s rotation period by several hours, significantly affect the magnitude of the Yarkovsky effect.
Cosmic Regulators of the Earth’s Climate
Authors: Avanesov G. A. , Zhukov B. S. , Mikhailov M. V. , Sherstyukov B. G.
Published: April 2024

A discussion is presented of the effects generated by the imbalance between the insolation energy of polar-day zones and the radiation energy of polar-night zones on multicentennial changes in the Earth’s climate. The dependence of this imbalance on the Earth’s orbital parameters is determined. The energy imbalance curves are compared with the known temperature curves for the polar regions, which have been estimated from the results of an analysis of ice cores taken in Antarctica and Greenland. The curves clearly reveal a difference between the contributions of cosmic and terrestrial factors to the temperature profiles for the regions in question and demonstrate a synchronicity of these factors. Algorithms are obtained for calculating the magnitude of fluctuations in the size of the Earth’s polar caps relative to their averages. The results obtained within the assumptions taken in this work enable predictions to be made about the development of the current global warming and about changes in the size of the Arctic and Antarctic polar caps. It is predicted that over the next three millennia, changes in the Earth’s orbital parameters will contribute to the slow melting of the northern polar cap. Then, the trend for a new growth of the northern polar cap will again manifest itself. In the Southern Hemisphere, a trend towards increased glaciation has already formed. Influenced by the cosmic factor, it will intensify over the next 20 000 years.
Non-gravitational Mechanism of Comets’ Ejection from the Oort Cloud Due to Cometary Outbursts
Authors: Belousov D. V. , Pavlov A. K.
Published: April 2024

Cometary nuclei located in the Oort cloud accumulate high concentration of radicals in surface layers under cosmic ray irradiation at low temperatures. Recombination of radicals induced by an increase in the surface temperature of a comet by a close passing star, O/B stars, or nearby supernovae leads to the heating of the ice layer with the releasing of volatiles from the amorphous ice. When high gas pressure builds up beneath the cometary surface, dust and gas are ejected. The resulting jet of gas and dust can change the comet’s orbit in the Oort cloud. The studied non-gravitational mechanism can effectively expel comets with a radius of ≤1 km from the Oort cloud into the inner part of the Solar system. The total effect of cometary outbursts on the stability of cometary orbits during the evolution of Solar system can result in a decrease in the number of long-period small-radius comets.
Analysis of the Evolution of the Moon and the Possible Dynamics of Its Body
Authors: Chujkova N. A. , Nasonova L. P. , Maksimova T. G.
Published: April 2024

The topography of the Moon’s surface and the possible distribution of density anomalies in its interior have been determined for the early stage of the Moon’s evolution. The distribution of gravitational anomalies and gravitational potential in various layers of the upper mantle has been found, which is due to the gravitational influence of anomalous structures of the crust and mantle. The analysis of the results leads to the conclusion about the possibility of convective motions in the molten electrically conductive layers of the crust and mantle, which could create an ancient magnetic field. For the current state of the lunar density structure, gravitational anomalies in various layers, which may lead to solid-state convection in some solidified regions of the Moon, have also been identified.
Studies of Isotopic Fractionation of D/H Water Ice in Lunar Regolith
Authors: Sevastyanov V. S. , Krivenkо А. P. , Voropaev S. А. , Marov M. Ya.
Published: April 2024

In order to study the processes related to the origin and retention of water on the surface of the Moon, an experimental setup has been created at the Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences (GEOKHI RAS), for the analysis of (re)sublimation processes of water ice in a vacuum at low temperatures. The temperature range for (re)sublimation varies from –100 to 0°C. The setup is connected to an Isotope Ratio Mass Spectrometer (IRMS), which allows for measuring the isotopic composition of the vapor of the evaporating substance and providing an estimation of the (re)sublimation rate under specific physicochemical conditions. The direct introduction of gases into the mass spectrometer in real-time mode sets the developed setup apart from foreign counterparts. The setup is equipped with a transparent quartz window through which the surface of the studied substance can be heated using a halogen lamp, simulating the movement of solar rays on the surface of mineral grain compositions under conditions similar to those on the lunar surface. In addition to studying gas (de)sorption on the surfaces of mineral grains of various compositions, the setup can also be used for researching the (re)sublimation of gas hydrates and CO2.
Study of Small Bodies of the Solar System: Odyssey-Asteroids Project
Authors: Slyuta E. N. , Shakhanov A. E. , El’nikov R. V.
Published: April 2024

The paper discusses priority scientific tasks related to the study of small bodies in the Solar System, identifies the most promising objects for investigation from a spacecraft on a flyby trajectory and the sample return mission, and develops proposals for the preliminary composition of scientific instruments for remote asteroid research methods. A long-term and phased Russian scientific program for studying small Solar System bodies using spacecraft with electric propulsion has been proposed. The project is designed in such a way as to explore the largest number of scientifically interesting asteroids using a smaller number of spacecraft. A design concept for a small spacecraft to investigate near-Earth asteroids on a flyby trajectory and a main spacecraft for studying metallic asteroids in the Main Belt and sample sample return has been developed. A ballistic analysis of the flyby of five near-Earth asteroids and three metallic asteroids in the Main Belt is presented, as well as a ballistic analysis of the sample return mission from a Main Belt asteroid. The option of sample return using the nuclear tug Zevs is also considered.
BEHAVIOR OF HEAVY METALS IN SOIL-CONDENSATE-PLANTS SYSTEM IN THE ULAN-UDE LANDFILLS
Authors: Cheredova T. V. , Doroshkevich S. G. , Bartanova S. V.
Published: April 2024

The impact of waste dumps on environmental components, i.e., soil, evaporating soil water (condensate) and plants is studied. It has been revealed that industrial and municipal waste dumps continue to affect significantly the environment after their closure. The behavior of heavy metals (Pb, Cu, Zn, Ni, Cd, Co, Sb, Sn, Bi, Hg, and Cr) in soils, plants, and condensate in landfill areas and beyond them (the background) has been studied in detail. It has been found out that soils, plants and condensate at landfills are enriched in heavy metals as compared to the background sites. The degree of soil contamination at waste dumps depends on the reclamation stage of the latter. The landfill soils exceed the norms of maximum permissible concentrations for heavy metals by 1.1–90 times. Concentrations of heavy metals in plants exceed the background values from 1.1 to 104 times at all dumps. The maximum level of heavy metals in plants is exceeded for Zn, Cd, Cr. In the condensate sampled at the dumps, MPC is exceeded for Cu, Zn, and Hg. Based on the analysis results, the geochemical rows of heavy metal distribution in different landfill environments were compiled: in plants – Zn Cu Cr Ni Pb Cd Co Hg Sn Bi; in condensate – Zn Cu Ni Cr Pb Sn Co Hg Sb Cd Bi; in the soil – Zn Cr Cu Ni Pb Co Sb = Sn Cd. The distribution of heavy metals in the condensate and plants is similar. In these environments, contribution of Zn and Cu is more than 80%, contribution of Cr, Ni, Pb varies from 1 to 10%; contribution of Cd, Co, Sb, Sn, Bi, Hg is less than 1%. Heavy metals are distributed in soil according to a different pattern: the main contributors are Zn and Cr (their input is more than 50%), then go Ni, Cu, Co, and Pb (their content in soil varies from 1 to 50%), followed by Sb, Sn, and Cd (their content is less than 1%). Total pollution indices (Zc) of the soil, condensate and plants have been calculated for each landfill. Based on Zc, the landfills were grouped in a ranking series, which can form the basis for assigning the sequence of landfill reclamation measures.
NATURAL PROCESSES AS JUSTIFICATION FACTORS FOR DECISIONS ON PORT HYDRAULIC STRUCTURES
Authors: Kantarzhi I. G. , Kuprin A. V.
Published: April 2024

The effects of sea waves and currents on harbour hydraulic structures are analysed from published open source data and the characteristics of scour from waves, including tsunami waves, are considered. Local bottom scour threatening the general stability of gravity-type engineering structures can arise under the effect of storm waves and currents, jets from ship propulsion devices and tsunami waves near hydraulic engineering structures. The types of scour mechanisms from sea waves have been investigated, i.e., local, general, and overtopping scour. There is a lack of sufficient measurement data for general scour to verify the calculation methods. Generally, general scour does not damage a structure, although it can contribute to its destruction by other types of scour when they overlap. Therefore, existing studies mainly focus on the analysis of local scour. The relationship between local scour and ground liquefaction and their influence on the stability of marine hydraulic structures is established. Failure mechanisms of hydraulic structures due to erosion by tsunami waves are analyzed: leeward and seaward toe scour, crown armour failure, parapet wall failure, sliding failure. The tsunami wave scour enhancement parameter is given, which is the fraction by which the pore pressure gradient reduces the frictional forces resisting scour. Significant ground instability occurs when the scour amplification parameter Λ exceeds a value of 0.5 (Λ ≥ 0.5). The parameter Λ can be used to assess areas where instantaneous liquefaction may be responsible for scour and sediment movement and to further recalculate erosion depths obtained without considering liquefaction. Liquefaction from a tsunami wave may penetrate up to 28% of the maximum erosion depth due to shear forces. The liquefaction phenomenon may occur due to a sudden drop in the water level in the area of return flow concentration. Consequently, the liquefaction phenomenon must be considered in the stability and erosion analysis around the structure.
APPROACHES TO STUDYING THE EFFECT OF GAS COMPONENT ON THE MECHANICAL PROPERTIES OF FROZEN SOILS
Authors: Khimenkov A. N. , Dernova E. O. , Stanilovskaya Yu. V.
Published: April 2024

Studies of recent decades have shown that the gas component plays a significant role in the structure and properties of frozen soils. This is indicated by a significant influx of greenhouse gases into the atmosphere from the permafrost; gas emissions leading to accidents at boreholes; the formation of gas emissions craters, etc. These processes are determined by the mutual influence between the characteristics of the gas component and the indicators of the physical and mechanical properties of frozen soils, which have not been studied enough to date. The formation mechanisms of gas-saturated zones are considered; the influence of gas on the physical and mechanical properties of thawed and frozen soils is assessed; and the processes associated with the impact of gas on the soil massif are analyzed.
NEOSTRUCTURAL ZONING OF THE RUSSIAN PART OF THE GREATER CAUCASUS MEGAVAULT, THE CENTRAL SEGMENT (ADVANCED STUDIES FOR ENGINEERING SURVEY)
Authors: Nesmeyanov S. A. , Voeikova O. A. , Komarevskaya M. N.
Published: April 2024

Detailed neostructural zoning with typification of tectonic structures should be performed before engineering surveys on the territory of the newest orogens or their large parts. A medium-scale neostructural zoning of the central segment of the Greater Caucasus megavault was carried out. It showed a significantly complex structure of the previously distinguished regional neotectonic bodies. The neotectonic structural plan is less differentiated in the north and east of the segment and it is more differentiated in the southern and western parts. A significant transformation of all local structures and regional suture zones is shown. It is connected with the fact that the newest structures are produced by orogenic uplift, and the older ones were formed under the conditions of horizontal compression. The results of neotectonic zoning are used in engineering, hydrogeological and geoecological surveys for construction design. They are important for paleoecological research, for example, in the study of archaeological sites.
Composites Based on Biodegradable Polymers and Layered Structures
Authors: Khlyustova A. V. , Agafonov A. V. , Titov V. A. , Evdokimova A. V. , Shibaeva V. D. , Kraev A. S. , Sirotkin N. A.
Published: April 2024

The paper presents the results of mechanical and electrical tests of composite materials based on biodegradable polymers (polyvinyl alcohol, polyacrylamide, starch) and synthetic layered double hydroxides (Ni–Al, Zn–Al) obtained by two-stage (chemical) and one-stage (plasma chemical) methods. The one-stage method for producing composites involves the formation of filler structures during the burning of low-temperature plasma in the bulk of an aqueous polymer solution. Electrode materials were used as precursors. Regardless of the production method, 2D hexagonal structures are formed and embedded in the polymer matrix. This is evidenced by IR spectroscopy data showing shifts in the main characteristic bands and the appearance of new ones. It has been established that layered fillers can be both plasticizers and reinforcing agents. The influence of the viscosity of the polymer matrix on the mechanical characteristics of the composites has been revealed. The introduction of fillers changes the surface roughness, leading to an increase in hydrophobicity of the composites. It has been established that the current–voltage curves of the composites are nonlinear, so that such composites can be considered as flexible analogues of nonlinear electronic components.
Prospects for Application of Guanidine-Containing Organomineral Complexes as Biocidal Functional Additives for Waterborne Polymer Materials
Authors: Gerasin V. A. , Zhurina M. V. , Kurenkov V. V. , Mendeleev D. I. , Ochenkov D. E. , Myat K. Htoo
Published: April 2024

The possibility of using organomineral complexes of polyhexamethylene guanidine hydrochloride as a functional additive for a waterborne paint based on polyvinyl acetate has been investigated. Organomineral complexes containing 20 and 30 wt % guanidine polymer have been obtained, with intercalation of polyguanidine chains into the interlayer space of montmorillonite being observed. It has been revealed that the stability of the polymer film to water is retained when organomineral complexes are introduced into a polyvinyl acetate dispersion, whereas the water resistance of the film sharply decreases when free polyguanidine is added. There was no significant influence of organomineral complexes on the rheological characteristics of the dispersion and its sedimentation stability. Testing of waterborne paints with various additives has shown that introduction of organomineral complexes into the material prevents the coating from fouling by biofilms of gram-positive bacteria Staphylococcus aureus and Rhodococcus erythropolis, with the hardness, water resistance, and water-vapor transmission of the coatings being retained at a satisfactory level.
Boron(III)-Containing Composite Hydrated Cellulose Fibers As Precursors of Carbon Materials
Authors: Egorov Yu. A. , Bondarenko G. N. , Vinogradov M. I. , Kulichikhin V. G.
Published: April 2024

Composite fibers containing boron(III) have been obtained based on solid solutions of cellulose in N-methylmorpholine-N-oxide and orthoboric acid with their subsequent transformation into a viscous-flow state. The rheological behavior of cellulose solutions with different content of orthoboric acid and water studied under conditions of continuous and dynamic shear loading has confirmed the intermolecular interaction between the components. It has been shown that the mechanical characteristics of the composite fibers obtained from a 16% solution in N-methylmorpholine-N-oxide are comparable to these for hydrated cellulose fibers. The process of transformation of the composite fibers of various compositions into carbon fiber has been investigated by means of thermogravimetric analysis and differential scanning calorimetry. Chemical, structural and morphological properties of composite hydrated cellulose fibers and carbon fibers obtained from them have been studied using FTIR-spectroscopy, X-ray diffraction, and scanning electron microscopy. The influence of boron(III) compounds on the carbonization process and the formation of graphite-like structures in carbon fiber has been investigated by Raman-spectroscopy.