Astronomy Letters-A Journal of Astronomy and Space Astrophysics最新文献_第6页

Dependence of the Nanoflare Occurrence Rate on the Solar Cycle Phase 纳米耀斑发生率与太阳周期阶段的关系

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S1063773725700501

Yu. A. Moiseev, S. A. Bogachev

{"title":"Dependence of the Nanoflare Occurrence Rate on the Solar Cycle Phase","authors":"Yu. A. Moiseev, S. A. Bogachev","doi":"10.1134/S1063773725700501","DOIUrl":"10.1134/S1063773725700501","url":null,"abstract":"We have used the SDO/AIA observational data obtained in the 171 Å channel to investigate the dependence of the occurrence rate of solar nanoflares observed in the vacuum ultraviolet spectral range on the solar cycle phase. For this purpose, we have processed more than 30 000 images obtained over the period from 2011 to 2020 inclusive that encompasses almost completely the 24th solar cycle and the beginning of the 25th cycle. To search for nanoflares, we have used the widespread method based on the selection of events that exceed the background by (5sigma) or more, which we have improved for a higher-quality removal of artifacts associated with charged particles. As a result, we have shown that in the periods of a high solar activity the number of nanoflares approximately doubles compared to their number at the solar cycle minimum. The change in the number of nanoflares is generally consistent with the change in the number of normal flares, although it occurs with a considerably lower amplitude. We have not detected any influence of the solar cycle on the energy distribution of nanoflares, nor have we detected any difference between large and small nanoflares, although we assume that it can exist. We also conclude that particle-associated artifacts are the main obstacle to the studies of nanoflares, and further progress is impossible without improving the methods of their removal.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 6","pages":"387 - 396"},"PeriodicalIF":0.8,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338399","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}

引用次数: 0

To the Formation and Heating Mechanisms of X-ray Bright Points on the Sun 太阳上x射线亮点的形成和加热机制

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S1063773725700513

A. V. Stepanov, V. V. Zaitsev, E. P. Ovchinnikova

{"title":"To the Formation and Heating Mechanisms of X-ray Bright Points on the Sun","authors":"A. V. Stepanov, V. V. Zaitsev, E. P. Ovchinnikova","doi":"10.1134/S1063773725700513","DOIUrl":"10.1134/S1063773725700513","url":null,"abstract":"We investigate the formation and heating mechanisms of X-ray bright points (XBPs) with which micro- and nanoflares in coronal holes and quiet regions, coronal heating, plasma jets and eruptions are associated. It follows from observations that XBPs consist of several compact magnetic loops that are considerably smaller than the coronal loops of active regions, but contain a plasma heated to a temperature of (1.5–4.4) MK. Using an ultrafine (({sim}100) km) magnetic loop being formed when the magnetic field is entrained by photospheric convection as an example, we show that the plasma in such loops is heated to temperatures of (2–4) MK through the dissipation of electric currents (Igeq 10^{9}) A in the chromospheric part of the loop at an increased Cowling resistivity. We have estimated the plasma density in XBP loops, (napprox 10^{9}{-}10^{10}) cm({}^{-3}), which is lower that the density of the surrounding chromosphere. Since the thermal conductivity of the loop along the magnetic field is considerably higher than that across the field, the loop rapidly heats up at the coronal level.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 6","pages":"382 - 386"},"PeriodicalIF":0.8,"publicationDate":"2026-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147338400","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}

引用次数: 0

Models of Long-Period Variables of the Globular Cluster 47 Tuc 球状星团47tuc的长周期变量模型

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2026-02-10 DOI: 10.1134/S1063773725700471

Yu. A. Fadeyev

引用次数: 0

Simulation of a Protoplanetary Disk Accretion Activity Due to a Collision with a Gas Stream 模拟因与气流碰撞而引起的原行星盘吸积活动

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700434

V. V. Grigoryev, T. V. Demidova

引用次数: 0

The Spiral Pattern Speed in the Milky Way Galaxy 银河系的螺旋形速度

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700422

V. V. Bobylev, A. T. Bajkova, A. A. Smirnov

{"title":"The Spiral Pattern Speed in the Milky Way Galaxy","authors":"V. V. Bobylev, A. T. Bajkova, A. A. Smirnov","doi":"10.1134/S1063773725700422","DOIUrl":"10.1134/S1063773725700422","url":null,"abstract":"Based on a sample of masers, we have solved the basic kinematic equations with the inclusion of the Galactic rotation parameters and the peculiar solar velocity as the sought-for unknowns. Based on a spectral analysis, we have obtained the following estimates: (|f|_{R,theta}=(7.0,5.1)pm(1.2,1.4)) km s({}^{-1}), the corresponding wavelengths (lambda_{R,theta}=(1.9,1.7)pm(0.4,0.7)) kpc, and (chi_{odot}={-}140^{circ}pm 15^{circ}). We have confirmed the presence of periodic perturbations in the vertical maser velocities with an amplitude (|f|_{W}=3.1pm 1.4) km s({}^{-1}) and a wavelength (lambda=1.9pm 0.8) kpc. We show that the velocity perturbations (f_{R}) and (f_{theta}) can have both the same and opposite signs. Therefore, we have obtained a large spread of estimates. For example, if (f_{R}) and (f_{theta}) have the same signs, then (Omega_{p}=25.8pm 2.0) km s({}^{-1}) kpc({}^{-1}) and (R_{textrm{cor}}=9.1pm 0.8) kpc, while if (f_{R}) and (f_{theta}) have opposite signs, then (Omega_{p}=35.4pm 2.0) km s({}^{-1}) kpc({}^{-1}) and (R_{textrm{cor}}=6.8pm 0.8) kpc.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 5","pages":"278 - 286"},"PeriodicalIF":0.8,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145779209","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}

引用次数: 0

MVN Space Experiment: The First Results of Its In-orbit Operation MVN空间实验：其在轨运行的初步结果

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700446

M. V. Buntov, N. P. Semena, V. V. Levin, S. V. Molkov, F. A. Voronin, D. M. Gamkov, A. G. Glushenko, E. B. Gurova, O. V. Demin, V. P. Konoshenko, A. V. Krivchenko, V. M. Kuznetsov, M. V. Kuznetsova, I. Yu. Lapshov, V. A. Lipilin, A. A. Lutovinov, A. V. Markov, A. M. Pristash, A. A. Rotin, D. V. Serbinov, D. V. Sibirtsev, D. M. Surin, V. V. Tambov, A. G. Toporkov, A. E. Shtykovskiy, G. A. Kharchenko

{"title":"MVN Space Experiment: The First Results of Its In-orbit Operation","authors":"M. V. Buntov, N. P. Semena, V. V. Levin, S. V. Molkov, F. A. Voronin, D. M. Gamkov, A. G. Glushenko, E. B. Gurova, O. V. Demin, V. P. Konoshenko, A. V. Krivchenko, V. M. Kuznetsov, M. V. Kuznetsova, I. Yu. Lapshov, V. A. Lipilin, A. A. Lutovinov, A. V. Markov, A. M. Pristash, A. A. Rotin, D. V. Serbinov, D. V. Sibirtsev, D. M. Surin, V. V. Tambov, A. G. Toporkov, A. E. Shtykovskiy, G. A. Kharchenko","doi":"10.1134/S1063773725700446","DOIUrl":"10.1134/S1063773725700446","url":null,"abstract":"We describe the scientific and technological goals of the ‘‘Monitor Vsego Neba’’ (MVN, All-Sky Monitor) space experiment and present its first results. This experiment began to operate onboard the International Space Station (ISS) on December 19, 2024. An analysis of the first results of its observations and the in-orbit operation of the equipment has shown that the basic MVN characteristics correspond to the declared ones in sensitivity, spatial, energy, and time resolution. We have obtained observational data for the brightest sources that can be used for the further calibration of the instrument. We have also determined the particle background of the Earth’s radiation belts and the constraints that are imposed by the enhanced background in the regions of the South Atlantic Anomaly and high latitudes on the observations of celestial sources. We have revealed a problem of the thermal regime of the detectors due to the off-design additional heat flow from the ISS surface that reduces the effective exposure time of observations. The technological goals of the experiment are successfully accomplished. An analysis of the operation of the equipment has shown the validity of the underlying software and hardware solutions. We present the possibility of extending the scientific part of the research with regard to direct X-ray observations of the Sun.","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 5","pages":"287 - 309"},"PeriodicalIF":0.8,"publicationDate":"2025-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145779258","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}

引用次数: 0

Cyclic Variations in the Mean Recurrence Times of Solar Flares in Active Regions 太阳耀斑在活动区平均重现时间的周期变化

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700409

Yu. A. Nagovitsyn, A. I. Larionova, A. A. Osipova

引用次数: 0

SN Ia CSM 2020aeuh: A Massive Binary C/O White Dwarf Merger? SN Ia CSM 2020aeuh：巨大的C/O双白矮星合并？

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700458

N. N. Chugai

引用次数: 0

Simulation of the Recording of the Brightest Gamma-ray Burst GRB 221009A by a Segmented Scintillation Detector 分段闪烁探测器记录最亮伽马暴GRB 221009A的模拟

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-12-19 DOI: 10.1134/S1063773725700410

A. A. Mkrtchyan, A. S. Pozanenko, P. Yu. Minaev, D. D. Frederiks

引用次数: 0

The Waldmeier Rule and its Modifications 瓦尔德迈尔规则及其修正

IF 0.8 4区物理与天体物理

Astronomy Letters-A Journal of Astronomy and Space Astrophysics Pub Date : 2025-11-28 DOI: 10.1134/S1063773725700331

Yu. A. Nagovitsyn, A. A. Osipova, S. N. Fedoseeva, A. I. Larionova

{"title":"The Waldmeier Rule and its Modifications","authors":"Yu. A. Nagovitsyn, A. A. Osipova, S. N. Fedoseeva, A. I. Larionova","doi":"10.1134/S1063773725700331","DOIUrl":"10.1134/S1063773725700331","url":null,"abstract":"We discuss the difference between the traditional Waldmeier rule and its various modifications related to the fact that the height of the 11-year cycle maxima is conditioned by the activity growth rates on the rising branches. We consider the closeness of the correlations between the Waldmeier effect, on the one hand, and its modifications that consider the activity growth rate from minimum to maximum instead of the length of the rising branch, on the other hand. Using Fisher’s test, we show that the traditional Waldmeier effect describes the observational data more poorly than does the modified one (with the argument of the maximum growth rate on the rising branch): the residual dispersion of data points for it is significantly larger (the significance level is (alpha=0.01)). Based on a series of total sunspot areas on a 400-year time scale (Nagovitsyn and Osipova 2021), we consider the correlation of its values at activity maxima (AR_{M}) with the mean rate of its change on the rising branches (MAR), including that during the Maunder minimum. We show that this correlation is nonlinear and close: the correlation coefficients for two different nonlinear fits, a parabola and a power law, are fairly large: (R=0.97{-}0.98).","PeriodicalId":55443,"journal":{"name":"Astronomy Letters-A Journal of Astronomy and Space Astrophysics","volume":"51 3","pages":"182 - 188"},"PeriodicalIF":0.8,"publicationDate":"2025-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145612976","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}

引用次数: 0