Solar System Research最新文献

The review examines the main aspects of the current state of observational meteor astronomy. Information is provided on the goals and objectives of observations, the modern equipment used, the methods of observations and data processing, the available international databases of accumulated network observational data and their contribution to the development of meteor astronomy and, in particular, to the establishment of new meteor showers. The current state of meteor observations in the post-Soviet space is considered. The meteor video observations launched as part of a joint Russian–Tajik project in 2024 could mark the beginning of the creation of a global meteor observation network in the territories of the Russian Federation and the Republic of Tajikistan. The progressive factors of modern observational meteor astronomy, as well as existing problems and prospects for further development are formulated.

The lunar soil analogue VI-75 fully corresponds to typical lunar regolith in terms of particle morphology, grain-size distribution, and physical-mechanical properties. It is actively used in various experimental studies and tests of space equipment and scientific instruments. This study investigates additional physical and mechanical characteristics of the lunar soil analogue VI-75, such as the angle of repose and the coefficients of subgrade reaction, which are essential for modeling and calculations when planning the placement of infrastructure for a permanent scientific lunar station on the Moon's surface. It is also shown that the water ice content in lunar soil can significantly alter its mechanical properties and greatly increase its strength characteristics. For example, doubling the water ice content in lunar regolith almost doubles its strength properties. The study addresses the rate of water migration due to gravity from the upper layer of the analogue to the lower layer and provides recommendations for preventing undesirable water migration during the preparation of experiments with frozen soil on large-scale test stands.

The degassing of material from the carbonaceous chondrite Dar al Gani (DaG) 190 (type CO3) was studied using a specially designed experimental setup. The results of experimental investigations on heating and isothermal holding (pyrolysis) of meteorite samples are presented, with the composition of released gases determined by gas chromatography. Raman spectra and IR spectra were obtained for both the primary material of DaG 190 (CO3 type) and after annealing at three temperatures: 200, 500, and 800°C. Based on these data, the thermal transformation process of the asteroid material—the parent body of the meteorite—was traced. A comparison was made with the degassing results of another carbonaceous chondrite, Allende (type CV3). Cosmochemical applications to the accretion processes of terrestrial planets are discussed, as well as the role of carbonaceous chondrites as sources of water, gases, and volatile compounds for the Moon and early Earth.

The calculation of nonhydrostatic stresses in the interior of Mars is carried out without taking into account the long-wave component. The numerical solution of the system of equations of elastic equilibrium for a gravitating planet was carried out on a grid with a resolution of 1° × 1° in latitude and longitude. Data on the topography and gravitational field of the planet, starting with the seventh harmonic, were used as boundary conditions. Most of the epicenters of marsquakes are located in zones of extensions and sufficiently large tangential stresses arising as a result of the planet’s deviation from the state of hydrostatic equilibrium. The directions of the main stress axes and their correspondence to the strike of geological structures on the planet’s surface are given.

A modern approach to thermodynamic modeling of developed turbulent flows of micropolar compressible fluid is considered, based on the application of the formalism of extended irreversible thermodynamics. The description of turbulent motion of turbulent fluid is carried out within the framework of the generalized continuum model consisting of two interconnected open subsystems—the averaged motion subsystem and the turbulent chaos subsystem (associated with small-scale vortex motion of the fluid). This made it possible to construct an evolutionary hyperbolic second-order closure model based on nonlinear constitutive equations of turbulent flow transfer using the generalized Gibbs equation and the general form of the entropy flux. The proposed methodology is in good agreement with the idea of A.N. Kolmogorov on the possibility of representing the pseudovector of angular velocity as an internal parameter for a thermodynamically open turbulent system if the scale of the differential grid exceeds the size of the mesovortices. It is this consideration that made it possible to develop continuous equations of turbulence that reflect the effect of internal rotation of turbulent mesovortices, as well as the case of a turbulent fluid with anisotropy of a vortex nature, which is related to the nonzero antisymmetric part of the Reynolds tensor. The results obtained can be used in studying the turbulent motions of micropolar fluids in the depths of stars, giant planets, as well as in the atmosphere of the Sun and other cosmic bodies.

Dust electrification and its associated electromagnetic (EM) emissions play a critical role in atmospheric and near-surface dynamics across planetary environments. This study provides a synthesis of recent work under publication that investigates the mechanisms of charge accumulation, electrostatic discharge, and electromagnetic radiation generation in dust-laden flows under both terrestrial and Mars-analog conditions, using a combined approach of analytical modeling, laboratory experiments, and field measurements. Laboratory experiments were conducted in the Earth conditions and in low-pressure CO₂-rich environments to simulate Martian conditions, employing silicate and basaltic samples across a range of grain sizes. The results demonstrate that triboelectric and tunneling charge transfer mechanisms, activated during vortex-driven particle dynamics, can induce transient discharges that generate broadband electromagnetic signals in the ~120–1500 kHz range. Under simulated Martian conditions, Paschen breakdown behavior was experimentally verified, confirming significantly lower breakdown thresholds compared to Earth’s atmosphere. Complementary field measurements carried out in the Kalmykian desert (Russia) further revealed that low humidity and intense solar radiation, even in the presence of moderate wind speeds, enhance dust electrification and discharge activity, leading to detectable EM emissions. Data were recorded using the Electromagnetic Analyzer (EMA), originally developed for Mars surface studies. Analysis of the recorded EM signal using time-domain analysis, Fast Fourier Transform (FFT), and continuous wavelet transform (CWT) revealed distinct amplitude-frequency signatures that correlate with particle properties and environmental drivers. These findings establish a new conceptual framework for understanding dust-driven EM phenomena in planetary atmospheres and underscore the applied relevance of electromagnetic diagnostics for future Mars, Moon, and Venus missions.

Combined measurements of ozone (O₃₎ and vibrationally excited hydroxyl (OH*) emissions allow determination of atomic oxygen (O) and hydrogen (H) concentrations, which are otherwise difficult to measure directly. This method is applicable only when ozone photochemical equilibrium (OPE) conditions are met. This paper is the first to investigate OPE in the nighttime atmosphere of Mars and its relationship to OH* emissions. Based on numerical modeling using data from Mars Climate Database (MCD), the spatiotemporal distributions of ozone deviations from the equilibrium state and the ratio of ozone lifetimes at current and equilibrium concentrations are analyzed. Two main OPE criteria are derived. The results show that OPE is satisfied over wide regions (65–90 km) in the second half of the Martian year (L_s = 180°–360°), especially at polar and midlatitudes. However, the regions with observed OH* concentrations ([OH*] ( geqslant )100 cm^–3) and satisfied OPE criteria are limited to the first half of the year (L_s = 0°–180°) and altitudes of 50–70 km. This indicates the difficulty of applying the method for retrieving O and H concentrations from OH* under Martian conditions without additional adaptation of the equilibrium criteria. Therefore, we test a criterion derived from the basic principles of photochemistry of the terrestrial mesosphere, mesopause, and lower thermosphere. The study highlights the need for further observations and refined models to correctly interpret chemical processes in the Martian atmosphere.

At present, planets like the Earth have been found near other stars. We investigate the spectra of Earth-like planets but with different axial rotation periods. Using the general circulation model of the atmosphere called the Community Climate Model (CCM3) and considering the atmospheric circulation lasting for two years, we calculated the radiation spectra of the Earth and the exo-Earth rotating with periods of 1 and 100 days, respectively. The radiation spectra of the atmospheres were calculated with the SBDART code. We analyzed the spectrum of upward radiation at altitudes of 1 and 11 km in wavelength ranges of 1 to 18 μm and 0.3 to 1 μm. The following common features were obtained for the Earth and the exo-Earth: (1) the planets exhibit a wide absorption band of CO₂ around 14 μm; (2) the radiation spectra at different locations near the equator show no significant differences (however, for some regions, e.g., near the poles, there can be considerable differences in the spectra); and (3) if the spectrum is integrated over the entire disk of the Earth/exo-Earth, the difference in the spectral signal obtained in observations from different directions becomes substantially lower than the difference between the results of observations of individual regions of the planets; however, the difference in the integrated signal of the spectrum for the Earth and the exo-Earth is noticeable (for example, this difference is noticeable for the spectrum obtained at an altitude of 11 km, when observing the South and North Poles; though, the difference is small, if one observes the whole disk from different equatorial directions). The differences in the spectra of exoplanets, which differ from the Earth only in axial rotation period, are comparable to the differences associated with changes in the angle of viewing the planet. Consequently, if the observation angle is not known, the analysis of the spectrum of the planet cannot be used to determine its axial rotation period. The maximal differences in the spectra of Earth-like exoplanets were obtained for wavelengths of about 5–10 and 13–16 μm. By analyzing the spectrum at wavelengths around 9.4–10 µm, we can determine whether the atmosphere of the exoplanet contains ozone or not. In the diagrams for the upward radiation at an altitude of 11 km, there is no local minimum at wavelengths of 9.4–10 µm if ozone is absent; and, when the models contain ozone, this minimum is present. Since ozone is essential for life, the 9.4–10 µm band may be important for future observations of Earth-like exoplanets.

Photogeological analysis of the upper Nirgal Vallis area, located in the northwestern part of the Noachis Terra highland plain, has shown that there were at least two episodes of fluvial activity in this area: the Noachis, which resulted in the formation of channels on the slopes of the ancient volcano, and the Hesperian, which formed Her Desher and Nirgal Vallis and channels on the southern slope of the northwestern ancient uplift. Similar results for determining the absolute model age of the formation of channels and large craters may indicate that impact activity in this region was the main cause of episodic warming. In addition, glacial activity may have occurred in the study area during early Amazonian times, forming an erosion area near Her Desher Vallis.