Chinese Astronomy and Astrophysics最新文献

{"title":"Lunar Infrared Spectral Study Based on Apollo and Chang'E-5 Samples","authors":"Chai Yi-min,&nbsp;Wu Yun-zhao,&nbsp;Wang Yang","doi":"10.1016/j.chinastron.2026.09.008","DOIUrl":"10.1016/j.chinastron.2026.09.008","url":null,"abstract":"<div><div>With the advancement of remote sensing technology and the rapid development of deep space exploration, thermal infrared hyperspectral remote sensing has become a frontier hotspot in planetary remote sensing. Infrared spectra contain rich information about the material composition, temperature, and surface physical properties of celestial bodies. Current research on the infrared spectra of the Moon is mainly based on the old Apollo samples, lacking studies on younger lunar soil samples. China's Chang'E-5 (CE-5) mission has for the first time collected young lunar soil, providing new samples for a deeper understanding of the thermal infrared spectral characteristics of the Moon. By comprehensively utilizing the spectral data of the old Apollo samples and the young CE-5 samples, the infrared spectral characteristics of the Moon were analyzed to reveal the influence of different terrains and maturity on the infrared spectra of the Moon. The results show that the overall shapes of the infrared spectra of different lunar terrains are similar, with the emissivity reaching its minimum around 4 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span> and then sharply increasing to reach its maximum around 8 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span>. There are differences in spectral characteristics among different terrains; the CF (Christiansen Frequency) value of the CE-5 samples is greater than that of most Apollo samples and is similar to that of Apollo 11, reflecting its mafic-rich nature. The plagioclase emissivity peak at 5.45 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span> is relatively pronounced in the CE-5 and Apollo 16 samples. The pyroxene emissivity valley at 11.4 <span><math><mrow><mi>μ</mi><mi>m</mi></mrow></math></span> is deeper in the CE-5 samples. Space weathering affects the infrared spectra of lunar soil, mainly manifested as an increase in the emissivity of RB (Reststrahlen Bands) and a decrease in spectral contrast. The CF characteristics of lunar soil are related to the SCFM (Si, Ca, Fe, Mg) index and are not significantly affected by maturity. The research results provide support for the thermal infrared hyperspectral remote sensing studies of the Moon and other celestial bodies.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 568-582"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wavefront Reconstruction Method Based on Multi-Feature Fusion in Neural Networks","authors":"Li Wen-long,&nbsp;Zhao Gang,&nbsp;Dou Jiang-pei,&nbsp;Zhu Yong-tian,&nbsp;Zhang Xi,&nbsp;Wang Gang","doi":"10.1016/j.chinastron.2026.09.010","DOIUrl":"10.1016/j.chinastron.2026.09.010","url":null,"abstract":"<div><div>The Shack-Hartmann Wavefront Sensor (SH-WFS) is widely used in adaptive optical systems. To fully utilize the information contained in SH-WFS images, a neural network-based wavefront reconstruction method called Moment-U-Net is proposed. Besides the centroid used in traditional wavefront reconstruction methods, this approach additionally uses spot intensity and second-order moment features to characterize spot shape information, enabling high-precision wavefront reconstruction. Moment-U-Net adopts U-Net as its main architecture and assembles feature extraction modules such as dense connection modules DenseBlock (Dense Convolutional Block) and channel attention mechanisms SEBlock (Squeeze-and-Excitation Block), allowing effective capture of higher-order aberration features during training. The model demonstrates excellent convergence when trained using large-scale simulated atmospheric phase and wavefront image data. Validation tests with simulated atmospheric turbulence of varying intensities show that Moment-U-Net achieves root mean square reconstruction errors ranging from 0.010 μm to 0.025 μm. Additionally, this method has high reconstruction precision for faint stars, achieving errors below 0.070 μm for 8th magnitude stars. Experimental results demonstrate that Moment-U-Net not only has high wavefront reconstruction precision, but also has strong generalization capabilities across different turbulence intensities and stellar magnitudes. This highlights its potential for practical observational applications to enhance the correction capabilities of adaptive optical systems.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 603-620"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Progress in Observations and Theories of GRB 221009A","authors":"Lin Yi-qing","doi":"10.1016/j.chinastron.2026.09.001","DOIUrl":"10.1016/j.chinastron.2026.09.001","url":null,"abstract":"<div><div>Recently, GRB 221009A, known as the brightest of all time (BOAT) Gamma-Ray Burst (GRB), has been detected by numerous space-based and ground-based telescopes across multiple wavelengths, including X-ray, <span><math><mi>γ</mi></math></span>-ray, optical, and radio bands. It is a relatively closer GRB (<span><math><mrow><mi>z</mi><mo>=</mo><mn>0.151</mn></mrow></math></span>) and the most energetic observed to date, with isotropic energy <span><math><mrow><msub><mi>E</mi><mtext>iso</mtext></msub><mo>≥</mo><msup><mn>10</mn><mn>48</mn></msup><mspace></mspace><mi>J</mi></mrow></math></span>. GRB 221009A, with its extraordinary brightness, TeV high-energy radiation, line spectral features around tens of MeV, and rich multi-wavelength data, provides new insights into key physical processes in the GRB theoretical framework, such as jet dynamics and shock radiation mechanisms. At the same time, it has empirically confirmed some theoretically predicted phenomena, (e.g., prompt annihilation lines and the lateral expansion of an ultra-narrow jet), driving the refinement of existing GRB theories under extreme parameter conditions. A brief review is presented regarding some of the observational breakthroughs and theoretical\tresearch progress associated with GRB 221009A.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 431-461"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Morphological Comparison of Three Algorithms for 13CO Clump Detection in the Milky Way Imaging Scroll Painting","authors":"Huang Yao,&nbsp;Chen Ying,&nbsp;Zheng Sheng,&nbsp;Liu De-jian,&nbsp;Chen Zhi-wei,&nbsp;Jiang Zhi-bo","doi":"10.1016/j.chinastron.2026.09.004","DOIUrl":"10.1016/j.chinastron.2026.09.004","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The objective evaluation of molecular clump detection algorithms is pivotal for unraveling the hierarchical structure of the interstellar medium and for revealing the physical processes that drive star formation. However, systematic comparisons of morphological differences and structural characterization capabilities among algorithms applied to real observational data are still lacking. We apply FellWalker, FacetClumps, and Dendrograms to &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;CO (&lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;J&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;mo&gt;−&lt;/mo&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;) spectral data from three representative regions of the Milky Way Imaging Scroll Painting (MWISP): 15.25&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 18.25&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, 0&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 1.5&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;; 100&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 110&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;|&lt;/mo&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mo&gt;|&lt;/mo&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 5.25&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;; and 180&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt; &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;mi&gt;l&lt;/mi&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 190&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mo&gt;|&lt;/mo&gt;&lt;mi&gt;b&lt;/mi&gt;&lt;mo&gt;|&lt;/mo&gt;&lt;mo&gt;≤&lt;/mo&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; 5.25&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mo&gt;∘&lt;/mo&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;. Here, &lt;em&gt;l&lt;/em&gt; and &lt;em&gt;b&lt;/em&gt; are respectively galactic longitude and latitude. Using Rotated J-values(RJ)-plots to classify the morphologies of &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;CO clumps, we find that the algorithm FacetClumps identifies a substantially higher fraction of centrally overdense and quasi-circular clumps in all three regions (all exceeding 85%), whereas FellWalker and Dendrograms detect a larger share of elongated structures, ranging from 20% to 40% of the detected clumps. A comparison based on C&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;18&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;O counterpart statistics in the M16 field shows that the centrally overdense and quasi-circular &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;CO clumps found by FellWalker and FacetClumps contain C&lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;18&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;O counterparts at rates of 77% and 91%, respectively. We further compute &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; column densities for the &lt;span&gt;&lt;math&gt;&lt;msup&gt;&lt;mrow&gt;&lt;/mrow&gt;&lt;mn&gt;13&lt;/mn&gt;&lt;/msup&gt;&lt;/math&gt;&lt;/span&gt;CO clumps and examine their relation to compactness. We ","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 494-516"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Recognition of Blazar Candidate of Uncertain Type Based on Effective Spectral Index","authors":"Liu Bei,&nbsp;Yang Jiang-he,&nbsp;Fan Jun-hui,&nbsp;Yang Wen-xin,&nbsp;Wang Sheng-hui,&nbsp;Tuo Man-xian,&nbsp;Bai Hong-zi,&nbsp;Chen Guang-qiang,&nbsp;Nie Jian-jun","doi":"10.1016/j.chinastron.2026.09.003","DOIUrl":"10.1016/j.chinastron.2026.09.003","url":null,"abstract":"<div><div>The Fermi-LAT (Large Area Telescope) source catalog contains approximately 4000 blazars, of which over 40% are classified as Blazar Candidates of Uncertain type (BCUs). Determining the precise classification of these BCUs is crucial for advancing our understanding of blazar properties. In this study, we analyzed a sample of Fermi blazars by calculating their effective spectral indices between each two of radio (R), optical (O), X-ray (X), and <span><math><mi>γ</mi></math></span>-ray (<span><math><mi>γ</mi></math></span>) bands, including <span><math><msub><mi>α</mi><mtext>RO</mtext></msub></math></span>, <span><math><msub><mi>α</mi><mtext>RX</mtext></msub></math></span>, <span><math><msub><mi>α</mi><mrow><mi>R</mi><mi>γ</mi></mrow></msub></math></span>, <span><math><msub><mi>α</mi><mtext>OX</mtext></msub></math></span>, <span><math><msub><mi>α</mi><mrow><mi>O</mi><mi>γ</mi></mrow></msub></math></span>, and <span><math><msub><mi>α</mi><mrow><mi>X</mi><mi>γ</mi></mrow></msub></math></span>. From this analysis, we obtained a sample of 3387 blazars with at least two valid spectral indices, consisting of 828 flat-spectrum radio quasars (FSRQs), 1382 BL Lacertae objects (BL Lacs), and 1177 BCUs. Using the effective spectral indices as feature parameters, we performed unsupervised classification on the 1177 BCUs via the Gustafson-Kessel (GK) fuzzy clustering algorithm. The results show that: among the 1177 BCUs, 904 were classified as FSRQs and 273 as BL Lacs. For the sources with inconsistent classifications between our study and previous literature, most were identified as FSRQs in our work but as BL Lacs in previous studies. From the perspective of multi-wavelength spectral indices, low-synchrotron-peaked BL Lacs (LBLs) exhibit similar radiation properties to FSRQs across multiple bands.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 477-493"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of the Pulse Nulling and Subpulse Drifting Properties from the Long-period Pulsar J1840-0840","authors":"Wang Hui,&nbsp;Wen Zhi-gang,&nbsp;Yuan Jian-ping,&nbsp;Wang Na,&nbsp;Han Wei,&nbsp;Yan Wen-ming,&nbsp;Chen Jian-ling,&nbsp;Wang Hong-guang,&nbsp;Wang Zhen,&nbsp;Gajjar Vishal","doi":"10.1016/j.chinastron.2026.09.005","DOIUrl":"10.1016/j.chinastron.2026.09.005","url":null,"abstract":"<div><div>This study presents a systematic investigation of the complex radiation behavior of the long-period pulsar J1840-0840 based on dual-frequency observations conducted with the Giant Metrewave Radio Telescope (GMRT) in India and the 100-meter Effelsberg radio telescope in Germany. The average pulse profile of this pulsar exhibits two distinct and spatially separated radiation components. The frequency evolution of the average profile is consistent with the theoretical predictions of the classical radius-frequency relation, indicating that the radio emission height of the pulsar systematically decreases with increasing observation frequency. Single-pulse analysis reveals significant pulse nulling and subpulse drifting characteristics in this pulsar. The nulling fractions at 625 MHz and 1358 MHz are 32.63%<span><math><mo>±</mo></math></span>10.46% and 28.36%<span><math><mo>±</mo></math></span>7.35%, respectively. The occurrence rates of both pulse burst and nulling states exhibit an exponential decay with increasing duration. Additionally, PSR J1840-0840 shows quasi-periodic nulling behavior, with two modulation periods at 625 MHz, namely (50.57<span><math><mo>±</mo></math></span>9.03) and (21.33<span><math><mo>±</mo></math></span>3.91) times the spin period, and one modulation period at 1358 MHz, which is (31.37<span><math><mo>±</mo></math></span>11.90) times the spin period. By modeling each drifting band, the phase separation, drift period, and drift rate evolution over time were obtained. The results indicate a significant frequency dependence of the subpulse drifting parameters.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 517-534"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Solar Interplanetary Propagation of Space Weather Events in May 2024","authors":"Liu Xiao-di,&nbsp;Zhong Ding-kun,&nbsp;Xiang Chang-qing","doi":"10.1016/j.chinastron.2026.09.006","DOIUrl":"10.1016/j.chinastron.2026.09.006","url":null,"abstract":"<div><div>A variety of observations are employed to conduct a preliminary analysis of the propagation in solar-interplanetary space of seven earth-directed full-halo Coronal Mass Ejections (CMEs) originating from the solar Active Region (AR) 13664 from 8 to 11 May 2024. These seven CMEs can be divided into two groups. The first group consists of four CMEs that occurred during the period from 05:36 UT on 8 May to 09:24 UT on 9 May, and the second group consists of three CME that occurred during the period from 18:52 UT on 9 May to 01:36 UT on 11 May. We utilize the Heliospheric Imager on the Solar Terrestrial Relations Observatory Ahead (STEREO A/HI) to track the time-elongation relationships of the high-density regions corresponding to these two groups of CMEs, and apply the fixed <span><math><mstyle><mi>Φ</mi></mstyle></math></span>-angle fitting method and the harmonic mean fitting method to calculate the most probable propagation directions and average radial velocities of these two groups of CMEs. The results show that the high-density regions associated with these two groups of CMEs are respectively overlapped in the field of view of STEREO A/HI. The minimum differences between the arrival times of the two CME groups near the EarthxA1xAFs orbit calculated from the fitting radial velocities and the actual start times observed by the WIND spacecraft are 0.5 hours and 3 hours respectively. These results indicate that during the solar-terrestrial propagation of these two groups of CMEs, the fast CMEs behind catch up with the slower CMEs ahead, thus, and the two groups of CMEs form two complex ejecta and generate the extremely intense geomagnetic storm.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 535-555"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of Lunar Tide-Generating Force Taking Lunar Shape into Account","authors":"Zhang Han-wei,&nbsp;Lu Zhi-xiang,&nbsp;Sun Na","doi":"10.1016/j.chinastron.2026.09.007","DOIUrl":"10.1016/j.chinastron.2026.09.007","url":null,"abstract":"<div><div>The establishment of the lunar observation platform can realize the large-scale, continuous, and long-term dynamic observation for the Earth, and can better meet the needs of scientific research on global change. In addition, it is also of great significance to study the early history and evolution of the moon and the Earth-moon system, as well as the deep structure and composition analysis. The construction and application of the lunar platform will certainly drive scientific and technological progress, stimulate industrial development, and have a profound impact on human civilization. The study of lunar tidal deformation is the basis of establishing high precision lunar observation platform. The tidal forces on the surface of the moon are about 20 times greater than those on the Earth, and the lunar tidal love number is less than an order of magnitude smaller than the Earth tidal love number. Therefore, the tidal effect on the lunar surface is significant. In this paper, the expression of tidal generating potential for any celestial body (including the moon), which takes into account its shape and can be expanded to any order, is given by using vector method. At the same time, a new Legendre polynomial recurrence relation is given.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 556-567"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-Resolution Galaxy Image Generation Based on Diffusion Models","authors":"Zhao Rui-ni,&nbsp;Wang Xing-feng,&nbsp;Lv Tao","doi":"10.1016/j.chinastron.2026.09.002","DOIUrl":"10.1016/j.chinastron.2026.09.002","url":null,"abstract":"<div><div>Against the backdrop of rapid advancements in both data accumulation within large-scale sky survey projects and information technology, the automated classification of massive galaxy images using intelligent methods has become a cornerstone for understanding galaxy formation, evolution, and the cosmic environment. The accuracy of galaxy classification models is significantly correlated with the scale and balance of training samples, yet traditional data augmentation methods exhibit limited effectiveness in enhancing complex galaxy images. The study proposes a diffusion model-based algorithm for generating galaxy images, which produces galaxy images with realistic morphological features and textural details. The classification model trained using the augmented dataset demonstrates superior precision, recall, and F1-score compared to the model trained on the original dataset, with maximum improvements of 4.01%, 4.3%, and 5.06% in the three metrics, respectively. These high-fidelity, clear generated images significantly improve the accuracy of galaxy morphological classification models. This process provides novel insights for future research on galaxy morphology classification in large-scale sky survey initiatives. Continued exploration of generative artificial intelligence models will provide powerful tools for astronomical research, enabling humanity to gain deeper insights into the mysteries of the universe.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 462-476"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on Machine Learning-Based Photometric Model for Low Earth Orbit Satellites","authors":"Li Juan,&nbsp;Zhang Xiao-ming,&nbsp;Qu Yao-bin,&nbsp;Wang Jian-feng,&nbsp;Wang Lei,&nbsp;Jiang Xiao-jun","doi":"10.1016/j.chinastron.2026.09.009","DOIUrl":"10.1016/j.chinastron.2026.09.009","url":null,"abstract":"<div><div>The photometric characteristics of satellites play an important role in analyzing their physical properties. An accurate photometric model can effectively support observation planning and strategy formulation, while also facilitating the analysis and interpretation of satellite attitude and structural characteristic changes. However, due to the rapid and complex variations in attitude and observation conditions during Low Earth Orbit (LEO) satellite transits, existing photometric models fail to accurately estimate the brightness of these satellites. To address this issue, we propose a modified spherical photometric model based on equivalent cross-sectional area, specifically designed for LEO satellites with stable attitude and orbit, and with observational data that sufficiently covers various viewing conditions. This method equates the satellite's cross-sectional area to that of a sphere with equal brightness. By incorporating the relative positional relationships among the satellite, the Sun, the observation station, and the orbital plane as key parameters, it employs machine learning algorithms to effectively fit and estimate the equivalent cross-sectional area, thereby enabling accurate photometric predictions during LEO satellite transits. To validate the effectiveness of the proposed method, we conducted performance evaluations using V-band photometric data from 7 LEO satellites observed by the 50 cm telescope at Xinglong Observatory, with comparisons made against the traditional spherical model. The results show that when sufficient observational data is available, the proposed method achieves higher accuracy and greater stability in photometric prediction, demonstrating strong reliability and broad applicability.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 3","pages":"Pages 583-602"},"PeriodicalIF":0.0,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148974577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}