Chinese Astronomy and Astrophysics最新文献

{"title":"Research on Image Reconstruction Method of Lunar Hydrogen Distribution Based on Simulation","authors":"Xiao-Li Mao ,&nbsp;Xue-Bo Zhu ,&nbsp;M.A. Tao ,&nbsp;Ren-Wei Cai ,&nbsp;Ke-Fan Wu","doi":"10.1016/j.chinastron.2025.05.008","DOIUrl":"10.1016/j.chinastron.2025.05.008","url":null,"abstract":"<div><div>Obtaining an accurate distribution map of lunar water hydrogen has significant scientific value for research on detecting water ice and for future deep space exploration. In order to effectively explore the water ice resources on the Moon, it is necessary to accurately detect their distribution. In practical applications, a point spread function with shifting characteristics is constructed based on the detection principle of neutron detectors and the process of satellite image degradation, due to the lack of effective and reliable image sources. The point spread function is based on the kappa function. The image is blurred and made noisy to create a simulated detection image. Then, the maximum entropy algorithm and Richardson-Lucy algorithm are utilized to reconstruct the simulated detection image. The evaluation criteria for comparative study include visual effect, chi-square test, and authenticity test. The experimental results show that direct reconstruction cannot achieve optimal reconstruction results under both low and high levels of noise. After applying denoising preprocessing, ensuring the safety of the chi-square test, the overall effect of the reconstruction results is found to be better than before preprocessing. Additionally, there is a significant reduction in the number of points with large deviation in the authenticity test of the reconstructed image. This indicates that the reconstruction results are now more accurate and reliable. It will provide more accurate data support for the exploration of water ice resources and deep space exploration.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 347-375"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261743","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":"Orbit Accuracy Simulation Analysis of Asteroid (469219) Kamoòalewa by Optical Observation of Tianwen-2","authors":"Yi-Xing Li ,&nbsp;Kai Tang ,&nbsp;Fan Min ,&nbsp;Yao-Bin Qu ,&nbsp;Yong Huang","doi":"10.1016/j.chinastron.2025.05.007","DOIUrl":"10.1016/j.chinastron.2025.05.007","url":null,"abstract":"<div><div>China’s asteroid exploration mission, Tianwen-2, is scheduled to launch in 2025. Its first target, asteroid (469219) Kamoòalewa (also known as 2016 HO3), is a near-Earth object in co-orbit with Earth, with significant research value in terms of its motion evolution. Currently, there are limited ground observation data available for asteroid (469219) Kamoòalewa, which restricts its orbit accuracy. Tianwen-2, equipped with an optical payload, is expected to acquire a large amount of onboard optical observation data during its approach to Kamoòalewa. This will greatly improve the study situation of asteroid (469219) Kamoòalewa, which currently has only ground-based optical observation data and lacks publicly available observation data after 2021. By simulating the optical observation data of Tianwen-2 with a spacecraft orbit error of 2 km, the pre-mission evaluation of the orbit prediction accuracy of asteroid (469219) Kamoòalewa has been completed. The precision evaluation was performed using covariance analysis and numerical comparison methods. Within the possible range of observation precision considered in this study, it is estimated that the optical observation data from Tianwen-2 can improve the overall orbit accuracy of asteroid (469219) Kamoòalewa to better than 15 km. Additionally, an analysis was conducted to examine the differences and characteristics of the results obtained from the two precision evaluation methods.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 376-393"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261744","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 Application of Unified Orbital Elements for Conic Orbits in Cislunar Orbit Prediction","authors":"Jia-Chun Wang ,&nbsp;Jing-Shi Tang","doi":"10.1016/j.chinastron.2025.05.010","DOIUrl":"10.1016/j.chinastron.2025.05.010","url":null,"abstract":"<div><div>When describing the motion of a spacecraft using traditional elliptical orbital elements, if its orbit changes from elliptical to hyperbolic, it becomes difficult to continue the calculation. In order to address this issue, improvements are made upon classical elliptical orbital elements, utilizing a set of orbital elements applicable to any conic section to integrate the equation of motion. The set of elements is applicable for any eccentricity <span><math><mrow><mi>e</mi><mi>⩾</mi><mn>0</mn></mrow></math></span> and inclination <span><math><mrow><mn>0</mn><mi>⩽</mi><mi>i</mi><mo>&lt;</mo><msup><mn>180</mn><mo>∘</mo></msup></mrow></math></span>, with the singularity occurring only for <span><math><mrow><mi>i</mi><mo>=</mo><msup><mn>180</mn><mo>∘</mo></msup></mrow></math></span>. The basic conversion formulas and equations of perturbed motion are provided. Subsequently, orbit predictions for cislunar objects are conducted, and the results are compared with calculations using Cartesian. The findings indicate that the results obtained from these orbital elements are sufficiently accurate, and the computational efficiency is advantageous when the changes in the elements are not particularly drastic. In addressing the issue of the singularity at <span><math><mrow><mi>i</mi><mo>=</mo><msup><mn>180</mn><mo>∘</mo></msup></mrow></math></span> that may arise in the practical application of orbital elements, various workarounds are proposed, including changing state variables and fixing integration step sizes, and their applicability is assessed.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 394-415"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261745","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 Factors Influencing the Shielding Effectiveness of Multi-layer Cavity Based on BLT Equation","authors":"Hu Mao-zhen ,&nbsp;Wang Yang ,&nbsp;Liu Qi ,&nbsp;Wang Na ,&nbsp;Tang Ren-kai ,&nbsp;Li Xiao-feng","doi":"10.1016/j.chinastron.2025.05.002","DOIUrl":"10.1016/j.chinastron.2025.05.002","url":null,"abstract":"<div><div>This paper centers on the technical problem of aperture coupling of multi-layer shielding cavity, and carries out the research on the influence of aperture coupling on the shielding effectiveness to provide technical support for the electromagnetic compatibility design of large radio telescopes. Based on Robinson model and electromagnetic topology theory, this paper establishes the equivalent circuit of a double-layer perforated shielding cavity and its signal flow diagram, and solves the shielding effectiveness using the BLT (Baum-Liu-Tesch) equation, taking into account the case of a 3-layer cavity. The accuracy of the measurement results, simulation values, Robinson's algorithm and this paper's algorithm are compared and analyzed, and the accuracy of this paper's algorithm is verified. On this basis, this method is used to analyze the influence of the layer spacing, the shape of the hole, and the installation position of the radiation source on the shielding effectiveness of the double-layer metal cavity in the 0–1.5 GHz band, and the engineering suggestions are given. In addition, the relationship between the number of layers of the three-layer shielding cavity and the shielding effectiveness is analyzed. The results show that there is a linear relationship between the shielding effectiveness and the number of layers.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 416-435"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261496","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 Measurement and Calculation Methods of Atmospheric Effects on Telescope Image Quality","authors":"Huang Shan-jie ,&nbsp;Zhao Jin-song ,&nbsp;Xu Fang-yu ,&nbsp;Wang Ling-xue ,&nbsp;Song Teng-fei ,&nbsp;Cai Yi","doi":"10.1016/j.chinastron.2025.05.004","DOIUrl":"10.1016/j.chinastron.2025.05.004","url":null,"abstract":"<div><div>The degradation of telescope image quality caused by atmospheric turbulence is currently an important factor restricting the high-resolution observation capability of ground-based astronomical telescopes. Measuring and calculating the effect of the atmosphere on telescope image quality is an important research direction in the field of astronomical technology. Firstly, the theoretical basis for measuring the effect of the atmosphere on image quality using optical and non-optical methods was elaborated, and representative technical routes, measurement results, and research progress of the two measurement methods were presented. The advantages and disadvantages of these measurement methods were analyzed in depth. Then, the basic principles and applicable ranges of three methods for calculating the effect of the telescope's internal airflow on the image quality of telescopes were summarized, and the advantages and disadvantages of these calculation methods were analyzed in depth. Finally, the technical characteristics of optical and non-optical measurement methods and computational methods were summarized, and an outlook on the future development direction of calculation methods was provided.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 280-316"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261738","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":"Dither Pattern and Results of Inflight Flat-field Calibration of the Lyman-alpha Solar Telescope onboard ASO-S Mission","authors":"Li Jing-wei ,&nbsp;Li Hui ,&nbsp;Feng Li ,&nbsp;Li Ying ,&nbsp;Huang Yu ,&nbsp;Li You-ping ,&nbsp;Zhao Jie ,&nbsp;Lu Lei ,&nbsp;Ying Bei-li ,&nbsp;Xue Jian-chao ,&nbsp;Ge Yun-yi ,&nbsp;Zhang Ping ,&nbsp;Song De-chao ,&nbsp;Li Qiao ,&nbsp;Li Shu-ting ,&nbsp;Tian Jun ,&nbsp;Li Gen ,&nbsp;Liu Xiao-feng ,&nbsp;Shi Guang-lu ,&nbsp;Shan Jia-hui ,&nbsp;Gan Wei-qun","doi":"10.1016/j.chinastron.2025.05.006","DOIUrl":"10.1016/j.chinastron.2025.05.006","url":null,"abstract":"<div><div>Before being used for scientific research, images obtained by solar telescopes with digital detectors must be corrected for flat-field, which reflects the non-uniformity coming from the non-uniform transmission efficiency of optical components and response of detector pixels. That means flat-field correction is a necessary step in the pipe-line of high-level scientific data. As one of the three payloads of the Kuafu-1 (Advanced Space-based Solar Observatory: ASO-S, Chinese name Kuafu-1) mission, the Lyman-alpha Solar Telescope (LST) consists of three scientific instruments: including a dual-waveband Solar Corona Imager (SCI), and two full-disk solar telescopes which are named the White-light Solar Telescope (WST) and the Solar Disk Imager (SDI). The WST and the SDI use Complementary Metal-Oxide-Semiconductor (CMOS) as image sensors, and the main feature of the flat field is the stripe structure which is caused by laser annealing. When used in the ultraviolet wavelengths, CMOS sensors will be subject to certain degradation and radiation damage, as well as the pollution of water vapor condensation and organic matter accumulation, which will have some influence on the obtained flat field. This paper mainly presents the dither pattern and its optimization used by the WST and the SDI in the in-flight flat field calibration since the launch of the ASO-S mission on 2022 October 9, the computed flat field images and their evolution during the period. We also briefly present the degradation and the radiation damage of the detectors in the WST and the SDI over time.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 456-477"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261495","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":"Particle-in-cell Simulation of Electromagnetic Field Structure in the Electron-only Reconnection","authors":"Shi-Hang Hu,&nbsp;Quan-Ming Lu,&nbsp;Yun-Dan Guan,&nbsp;L.U. San","doi":"10.1016/j.chinastron.2025.05.003","DOIUrl":"10.1016/j.chinastron.2025.05.003","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Standard collisionless magnetic reconnection couples with both electron and ion dynamics. Recently, a new type of magnetic reconnection, electron-only magnetic reconnection without ion outflow, has been observed. Using 2.5D particle-in-cell simulation, the electromagnetic field structure in the electron-only reconnection with a strong guide field was studied. At the moment of the maximum reconnection rate, the electron inflow and outflow are observed on either side of the separatrix. The spatial distribution of the electron bulk velocity is approximately symmetric, which generates the nearly symmetrically distributed Hall current, resulting in the quadrupole Hall magnetic field. The Hall magnetic field is not obviously distorted despite the presence of the strong guide field. Meanwhile, the charge separation is caused in the separatrix region, which generates the nearly symmetrically distributed Hall electric field. Besides, the evolution of the spatial distribution of the electron bulk velocity was studied. The equation of motion for the frozen electrons was analytically obtained: &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msubsup&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msubsup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. According to the equation of motion for the electrons, we divide the electron-only reconnection with a strong guide field into two stages. In the first stage, the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; drift is negligible because of the weaker Hall electric field, and then the electrons flow mainly along the magnetic field line following the equation &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mrow&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. In the second stage, the Hall electric field is so strong that the motion of electrons is dominated by the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; drift following the equation &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;v&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;≈&lt;/mo&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mi&gt;e&lt;/mi&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;mo&gt;/&lt;/mo&gt;&lt;msubsup&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;mrow&gt;&lt;mi&gt;y&lt;/mi&gt;&lt;/mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msubsup&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. The simulation shows that extremely strong charge separation can be caused in electron-only reconnection, which generates the nearly symmetrically distributed Hall electric field. With a guide field, this Hall electric field leads to the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;E&lt;/mi&gt;&lt;mo&gt;×&lt;/mo&gt;&lt;mi&gt;B&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; drift, which dominates the spatial distribution of the electron bu","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 267-279"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261737","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 Relationship between the Inverse Compton Peak Frequency and the γ-ray Photon Spectral Index for Blazars","authors":"Tuo Man-xian ,&nbsp;Yang Jiang-he ,&nbsp;Zhang Yue-lian ,&nbsp;Wang Sheng-hui ,&nbsp;Nie Jian-jun ,&nbsp;Fan Jun-hui","doi":"10.1016/j.chinastron.2025.05.009","DOIUrl":"10.1016/j.chinastron.2025.05.009","url":null,"abstract":"<div><div>The relationship between the inverse Compton peak frequency (<span><math><mrow><mi>lg</mi><msubsup><mi>ν</mi><mrow><mi>p</mi></mrow><mtext>IC</mtext></msubsup></mrow></math></span>) and <span><math><mi>γ</mi></math></span>-ray photon spectral index ({rm <span><math><mstyle><mi>Γ</mi></mstyle></math></span>}) for different subclasses of blazars was studied using Fermi/LAT (Large Area Telescope) 4FGL-DR3 (The 4th Fermi Gamma-ray LAT-Data Release 3) blazars as a sample. The results show that: there is a strong negative correlation between <span><math><mrow><mi>lg</mi><msubsup><mi>ν</mi><mi>p</mi><mtext>IC</mtext></msubsup></mrow></math></span> and <span><math><mstyle><mi>Γ</mi></mstyle></math></span> for all subclass samples of blazars, indicating that the <span><math><mi>γ</mi></math></span>-ray photon spectral index has a strong dominant effect on the inverse Compton spectrum of blazars, and the inverse Compton peak frequency can be quickly estimated using the relationship between them. The spectrum energy distributions (SEDs) of the inverse Compton emission for different subclass sample of blazars may have different spectral structure functions. Therefore, for different samples, different functions should be used to fit their SEDs.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 317-328"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261739","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":"Progenitor Evolution of the Double Neutron Star System J1846-0513","authors":"Jiang Long ,&nbsp;Fan Yun-ning ,&nbsp;Xu Kun ,&nbsp;Chen Wen-cong","doi":"10.1016/j.chinastron.2025.05.005","DOIUrl":"10.1016/j.chinastron.2025.05.005","url":null,"abstract":"<div><div>J1846-0513 is a millisecond pulsar discovered by the Five-hundred-meter Aperture Spherical radio Telescope (FAST) which is established by China. Data analysis of observation reveals that the pulsar is harbored in a binary with orbital period of <span><math><mrow><msub><mi>P</mi><mtext>orb</mtext></msub><mo>=</mo></mrow></math></span> 0.613 d and eccentricity of <span><math><mrow><mi>e</mi><mo>=</mo><mn>0.208</mn></mrow></math></span>. According to the theory of binary evolution, its eccentricity originates from an asymmetric supernova explosion during which the second neutron star was born. Together with the observed parameters of component mass, the binary is assumed to be a double neutron star system candidate. Considering its importance to understand the evolution of stars and binaries, in current work, we simulated the evolution of neutron star – helium (He) star system with initial mass of <span><math><mrow><mn>1.345</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span> and <span><math><mrow><mn>2.8</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span>, respectively, and initial orbital period of 0.5 day. At the end of the simulation, the total mass of the He star is reduced to <span><math><mrow><mn>1.556</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span> with a carbon-oxygen core with mass of <span><math><mrow><mn>1.431</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span>. A silicon core of mass <span><math><mrow><mn>0.846</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span> and an iron/neutron-rich core of mass <span><math><mrow><mn>0.086</mn><mspace></mspace><msub><mi>M</mi><mo>⊙</mo></msub></mrow></math></span> formed in the He star which illustrate it will end with core collapse supernova, and born a neutron star with mass of measured lower limit. Subsequent simulation of dynamical effects of the supernova explosion indicates that current model may evolve to the observed eccentric double neutron star candidate.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 329-346"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261742","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":"Discrimination of Stellar Contamination in Exoplanet Transmission Spectra with CSST/MCI","authors":"Deng Ying-ping ,&nbsp;Jiang Cheng-zi ,&nbsp;Chen Guo ,&nbsp;Yan Zhao-jun","doi":"10.1016/j.chinastron.2025.05.001","DOIUrl":"10.1016/j.chinastron.2025.05.001","url":null,"abstract":"<div><div>The Chinese Survey Space Telescope (CSST) is expected to characterize the atmospheres of exoplanets, providing new opportunities for exoplanet observations. At present, the atmospheres of exoplanets have mostly been studied by transmission spectroscopy. However, evidence of stellar activity has been found in several observed transmission spectra, and the results show that it is difficult to accurately constrain the stellar contamination. Therefore, how to accurately distinguish and eliminate stellar contamination has become a major challenge in transmission spectroscopy. Consequently, a quantitative assessment of the potential stellar contamination and its distinguishability is required when selecting targets for follow-up transmission spectroscopy observations, which requires large-scale simulations to provide the expected data. Here we use multi-color photometry combined with machine learning to identify potential stellar contamination in the transmission spectra of extrasolar gas planets, and design a filter combination with the highest accuracy for stellar contamination discrimination for the CSST Multi-Channel Imager (MCI), which can provide options for developing observing strategies for follow-up observations of exoplanet atmospheric targets.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"49 2","pages":"Pages 436-455"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144261746","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}