Astronomy Reports最新文献

{"title":"Study of the Development of ICME Induced Geomagnetic Storms during Solar Cycle 24","authors":"B. Aljehani,&nbsp;B. Badruddin,&nbsp;M. Derouich","doi":"10.1134/S1063772926700010","DOIUrl":"10.1134/S1063772926700010","url":null,"abstract":"<p>We aim to study the development of strong geomagnetic storms (GS) triggered by interplanetary coronal mass ejections (ICMEs). To this end, we selected 25 events from Solar Cycle 24 and characterized their behavior during their near-Earth passage. A cross-correlation analysis was conducted to determine the time lag between geomagnetic indices, such as the disturbance storm time (<i>Dst</i>) index and the horizontal component of the symmetric disturbance (<i>SYMH</i>) index, and solar wind parameters, using data with 1-hour and 1-minute resolutions. An exponential fit was applied to the recovery profiles of ICME-associated GS events for the hourly <i>Dst</i> index and specific plasma/field parameters. Our results indicate a time lag between the north–south component of the interplanetary magnetic field (IMF) <i>Bz</i> and the dawn-dusk electric field <i>Ey</i> with geomagnetic indices (<i>Dst</i>/<i>SYM-H</i>), similar for both. Additionally, the time constant of the <i>Dst</i> is reasonably correlated with the time constants of <i>Bz</i> and <i>Ey</i>. These findings would enhance our understanding of geomagnetic storm evolution and could contribute to improving space weather forecasts and our comprehension of solar–Earth interactions.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 12","pages":"1497 - 1513"},"PeriodicalIF":0.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparison of Three Approaches to Determining Orbits of Visual Double Stars Based on Observations of Their Short-Arced Orbits","authors":"O. V. Kiyaeva,&nbsp;I. S. Izmailov","doi":"10.1134/S1063772925702415","DOIUrl":"10.1134/S1063772925702415","url":null,"abstract":"<p>Using model examples and the results of actual published observations, three methods currently used at the Pulkovo Observatory are compared: (1) The Thiele–Innes element method, developed by I.S. Izmailov. Unlike the classical Thiele–Innes method, suitable for short-period doubel stars, in this case the orbital period, eccentricity, and periastron passage moment are determined using a Monte Carlo method with subsequent refinement. No additional data are required. (2) The apparent motion parameter (AMP) method, proposed by A.A. Kiselev in 1980. This is a direct method in which the initial parameters obtained from high-precision homogeneous positional observations are held constant, while remote heterogeneous observations serve as self-checks for the resulting solution. Additional parameters are also used: parallax, radial velocities, and masses. Two solutions or a family of orbits are obtained over a short arc, from which a single solution can sometimes be selected. The method requires an individual approach for each specific star. (3) The AMP2 method, according to I.S. Izmailov’s algorithm, in which the initial parameters are not fixed, but are refined iteratively over all observations using fixed radial velocity observations. The advantage of this method is the ability to determine stellar orbits and masses on a large scale. The results of model studies are compared with those of published catalogs. This article is partially based on a paper presented at the Modern Stellar Astronomy 2025 conference.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 12","pages":"1315 - 1325"},"PeriodicalIF":0.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Infall onto the Protoplanetary Disk during the Gravitational Collapse of a Molecular Cloud","authors":"E. R. Redkin,&nbsp;E. I. Vorobyov","doi":"10.1134/S1063772925702476","DOIUrl":"10.1134/S1063772925702476","url":null,"abstract":"<p>The development of models for matter infall from a collapsing molecular cloud is an essential part of numerical studies on the formation and evolution of protoplanetary disks. In this article, the widely used Nakamoto and Nakagawa model [7] is analyzed and modifications are proposed to complement the initial model. These improvements include calculation for the outer boundary of a molecular cloud and refinement of the initial density distribution within. Also, due to the finite size of a cloud, the approach for computing the rate of mass infall onto the protoplanetary disk during collapse is modified. The proposed enhancements are aimed at eliminating the key limitations of the initial model, but do not affect its advantages, such as simplicity in numerical implementation. Using the modified model, we investigate the duration of the embedded phase of the evolution of young stellar objects and compare the modeling results with observational data. The results indicate a shorter duration of the embedded phase of the evolution of young stellar objects, especially in star-forming regions with a high amplitude of the initial density perturbation of prestellar condensation.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 12","pages":"1281 - 1294"},"PeriodicalIF":0.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spectral and Photometric Characteristics of LBV Candidates in the Dwarf Galaxy UGC 12588","authors":"Yu. N. Solovyeva,&nbsp;A. S. Vinokurov,&nbsp;S. A. Pustilnik,&nbsp;E. O. Dedov,&nbsp;O. N. Sholukhova","doi":"10.1134/S1063772925702506","DOIUrl":"10.1134/S1063772925702506","url":null,"abstract":"<p>—We have searched for luminous blue variables (LBVs) in the galaxy UGC 12588 with Hubble Space Telescope data and selected 9 candidates brighter than <span>({m_{{text{F606W}}}}{ &lt; 22^m})</span> that are accessible for spectral observation with the 6-meter Russian telescope. For all candidates, the age of the nearest stellar associations was estimated. To date, we have obtained spectra for 6 objects. Based on the analysis of the acquired data, we derived estimates of the interstellar reddening towards the studied sources using the observed Balmer decrement in the spectra of the surrounding nebulae. From the spectrum of the galaxy’s brightest HII region, we determined the abundances of oxygen. Using these measurements, we estimated the metallicity of the gaseous environment and the young stellar population. In the combined spectrum of two closely located objects, s1 and s4 (J232443.72+412116.4 and J232443.77+412116.3, respectively), we identified blends of lines characteristic of Wolf–Rayet stars. However, these features likely belong to fainter stars in the association that are not spatially resolved from s1 and s4 in our ground-based observations. The spectra of the other three objects did not reveal neither signature features of the LBV stars nor indicators of significant mass loss in a wind. The source s2 (J232441.99+412110.2) emerged as the most promising LBV candidate as its spectrum shows broad and strong hydrogen emission lines (Hα with EW ≈ 120 Å). Photometric data from 2020–2024 revealed its brightness variability with an amplitude of <span>(Delta {R_c} = 0.80 pm {0.06^m})</span>. In contrast, the brightness variations of the other objects in the sample are in the range of <span>(0.2{-} {0.4^m})</span>, with a significance not exceeding <span>(5sigma )</span>. However, the observed positive correlation between the <span>(V - {R_c})</span> color and the <i>V</i>-band brightness of s2 is more typical of yellow hypergiants than of LBVs. Additional observations, particularly in the infrared range, are required to determine the nature of this object. Such observations will be crucial to check for the presence of a circumstellar dust shell, which is a common feature of yellow hypergiants. This work is partially based on a talk presented at the “Modern Stellar Astronomy—2025” conference.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 12","pages":"1269 - 1280"},"PeriodicalIF":0.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Formation of Nitrogen-Containing Aromatic Compounds in the Envelopes of Asymptotic Giant Branch Stars","authors":"A. A. Nikolayev,&nbsp;V. S. Krasnoukhov,&nbsp;P. S. Pivovarov,&nbsp;I. O. Antonov,&nbsp;V. N. Azyazov","doi":"10.1134/S106377292670006X","DOIUrl":"10.1134/S106377292670006X","url":null,"abstract":"<p>The formation of the bicyclic N‑heterocyclic aromatic compound indole (C₈H₇N) from aniline (C₆H₅NH₂) has been shown to proceed via the widely recognized “hydrogen abstraction–acetylene addition” (HACA) mechanism that is commonly employed to describe molecular mass growth in polycyclic aromatic hydrocarbons. Hydrogen abstraction from the NH₂ functional group produces the N‑phenylamino radical (C₆H₅NH), whereas abstraction from the benzene ring produces the <i>o</i>‑aminophenyl radical (C₆H₄NH₂). The mechanisms and kinetics of reactions between acetylene (C₂H₂) and the C₆H₅NH and C₆H₄NH₂ radicals under the conditions of carbon‑rich circumstellar envelopes of asymptotic giant branch (AGB) stars have been elucidated using high‑level quantum chemical methods combined with advanced transition state theory. Based on the constructed potential energy surface diagrams and calculated dependencies of the kinetic constants of the processes, the reaction paths and their relative contributions to the composition of the final products have been identified. Notably, under AGB stellar envelope conditions, indole formation dominates over all other reaction products at temperatures of <i>T</i> &lt; 2000 K.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 12","pages":"1477 - 1487"},"PeriodicalIF":0.7,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147579335","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of High-Doses Ionizing Radiation on Photosynthesis of Wheat Plants at Various Light Intensities","authors":"M. A. Grinberg,&nbsp;Yu. A. Nemtsova,&nbsp;V. A. Vodeneev","doi":"10.1134/S1063772925702555","DOIUrl":"10.1134/S1063772925702555","url":null,"abstract":"<p>Long-term manned space missions require the design and construction of “space greenhouses” to replenish food supplies and regenerate the atmosphere. Increased levels of ionizing radiation outside the Earth’s magnetosphere can significantly affect the efficiency of photosynthesis, the process by which plants use light energy to synthesize organic matter and produce oxygen. Identifying the mechanisms of the effect of ionizing radiation on photosynthesis and determining the optimal parameters for the operation of space greenhouses can help compensate for the impact of space conditions on plant productivity. This paper shows that irradiation of wheat plants (<i>Triticum aestivum</i> L.) at a dose of 100 Gy significantly increases the rate of plant development and disrupts their ability to use light energy in photosynthesis. A range of illumination intensities was found at which the efficiency of light energy use in irradiated plants coincided with this parameter in control plants. The disruption of the connection between photosystem II and the antenna of the light-harvesting complex caused by oxidative stress is assumed to be the mechanism of the identified imbalance in the functioning of the photosynthetic apparatus.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 1","pages":"S14 - S20"},"PeriodicalIF":0.7,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simulation of Transverse Collisionless Jets in Laser Plasma Experiments","authors":"I. F. Shaikhislamov,&nbsp;A. A. Chibranov,&nbsp;A. E. Ivanov,&nbsp;A. G. Berezutsky,&nbsp;V. G. Posukh,&nbsp;M. V. Loginov,&nbsp;P. A. Trushin,&nbsp;M. S. Rumenskikh,&nbsp;Yu. P. Zakharov,&nbsp;I. B. Miroshnichenko,&nbsp;V. A. Terekhin,&nbsp;A. V. Terekhin,&nbsp;R. S. Zemskov","doi":"10.1134/S1063772925702622","DOIUrl":"10.1134/S1063772925702622","url":null,"abstract":"<p>The paper presents the results of a laboratory experiment with detailed measurements of the dynamics and spatial structure of a plasma flow similar to astrophysical jets. For the first time in such experiments, the magnetic field component generated by a shear flow in a rarefied background plasma was measured. It was shown that it can be interpreted as an Alfvén wing. The drift electric field in the jet propagation region was also measured. All these findings confirm that the external magnetic field remains frozen into the plasma flow throughout its propagation over distances significantly exceeding the ion’s Larmor radius.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 1","pages":"S91 - S102"},"PeriodicalIF":0.7,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of the Effects of Magnetic Field Inhomogeneities in an Incubator on the Growth Rate of Human Cells in the Context of Modeling Astrogeophysical Conditions","authors":"M. A. Karpova,&nbsp;L. M. Sencha,&nbsp;A. A. Dolinin,&nbsp;F. G. Sarafanov,&nbsp;N. V. Ilin,&nbsp;S. A. Mysyagin,&nbsp;V. A. Vodeneev,&nbsp;M. A. Grinberg,&nbsp;E. A. Mareev,&nbsp;I. V. Balalaeva","doi":"10.1134/S1063772925702579","DOIUrl":"10.1134/S1063772925702579","url":null,"abstract":"<p>The magnetic field, including hypomagnetic conditions, is a key astrogeophysical factor that requires comprehensive study of its effects on living systems. Planned interplanetary missions will, on the one hand, encounter the absence of Earth’s geomagnetic field and, on the other, face strong inhomogeneity in the spacecraft’s own magnetic field. Of particular interest is how both the amplitude and the spatial characteristics of magnetic-field inhomogeneity affect human cells under laboratory conditions simulating orbital environments. In vitro cell culture under strictly controlled incubator conditions is a common experimental approach in biological research. CO₂-incubators provide control over temperature, gas composition, and humidity. Recent studies report that incubators can significantly alter the ambient magnetic field. Here, we show that two types of CO₂-incubators substantially modify magnetic-field parameters, and that the nature of these modifications depends on the incubator model. One incubator exhibited pronounced spatial inhomogeneity of the magnetic field, with regions of both low and high field strength. The other incubator, during operation, generated magnetic-field oscillations with period of oscillations about several seconds and peak-to-peak amplitude exceeding the mean value. We found that the magnetic background markedly affects the growth of human embryonic kidney cells. The effect of an ultra-low-frequency (ULF) magnetic field with a period of several seconds was especially pronounced and is relevant to space applications. Nutrient-deficiency-induced stress increased cellular sensitivity to this factor. These results emphasize the importance of weak static and time-varying magnetic fields for cell-growth processes, particularly in combination with other adverse conditions.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 1","pages":"S28 - S39"},"PeriodicalIF":0.7,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MHD Simulations of Magnetized Rotating Jets","authors":"O. D. Toropina,&nbsp;G. S. Bisnovatyi-Kogan,&nbsp;S. G. Moiseenko","doi":"10.1134/S1063772925702610","DOIUrl":"10.1134/S1063772925702610","url":null,"abstract":"<p>The results of MHD simulations of supersonic astrophysical and laboratory jets in an external poloidal magnetic field (<span>({{B}_{r}})</span>, <span>({{B}_{z}})</span>) taking into account the rotation of the matter, are presented. The ejected matter is collimated by the magnetic field, the degree of collimation and the flow structure depend on the relation between of the magnetic field induction and the angular velocity of the matter. For a strong magnetic field and moderate rotation, a barrel-shaped structure of an elongated shape is formed, which leaves behind a stable outflow. Inside the jet ejection, a barrel-shaped a periodic shock-wave structure is observed. For a moderate magnetic field and rapid rotation, the ejected matter at first significantly expands, but then gradually collimates into a jet due to the appearance of a toroidal magnetic field <span>({{B}_{phi }})</span>. A cocoon-shaped structure is formed. It spreads to the boundary of the computational domain. Inside the jet cocoon, a cavity with a low density of matter, quasi-stationary in time near is formed. In all cases, the rotation of the matter in the jet is transmitted to neighboring regions, which ultimately leads to the generation of magneto-torsional oscillations associated with the appearance of a toroidal component of the field. The toroidal field <span>({{B}_{phi }})</span> arises during the twisting of the poloidal magnetic field due to the dependence of the jet matter angular velocity on the radial (<span>(r)</span>) and axial (<span>(z)</span>) coordinates. The toroidal field also participates in the collimation of the jet.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 1","pages":"S80 - S90"},"PeriodicalIF":0.7,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341778","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-Ray Spectral Diagnostics of the Interaction Region of a Supersonic Plasma Flow with a Gas Wall in Laboratory Experiments with Astrophysical Similarity","authors":"S. N. Ryazantsev,&nbsp;I. Yu. Skobelev,&nbsp;S. S. Makarov","doi":"10.1134/S1063772925702609","DOIUrl":"10.1134/S1063772925702609","url":null,"abstract":"<p>The article deals with the possibility of using high-resolution imaging X-ray spectroscopy to study the parameters of the interaction region of a laser-plasma aluminium supersonic flow (jet) with an argon gas wall in a model experiment with astrophysical similarity to Herbig–Haro objects. Experiments of this kind are promising for the realisation with modern nanosecond laser complexes with a pulse energy of several tens of J up to several kJ (intensity <i>I</i>_las ~ 10¹²–10¹⁴ W/cm²) and can extend the understanding of the processes taking place in the space environment as well as verify existing theoretical models. The modelling of the laboratory object was carried out in 2 stages—first the macroscopic properties of the object were calculated using a hydrodynamic simulation, and then the calculated spatio-temporal profiles of the macroscopic parameters were fed into a non-stationary kinetic code, which was used to model the radiative properties of the process under consideration. It is shown that the simulated X-ray spectrograms allow to estimate the plasma parameters in the interaction region of the laser-plasma jet with the gas cloud based on the relative intensities of the spectral lines of multiply charged argon ions and the location of this region based on the spatial distribution of the argon ion glow.</p>","PeriodicalId":55440,"journal":{"name":"Astronomy Reports","volume":"69 1","pages":"S69 - S79"},"PeriodicalIF":0.7,"publicationDate":"2026-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147341790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}