Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.004
Zeng Shu-guang , Zhang Jun-jie , Huang Yao , Liu De-jian , Zhang Peng , Jiang Zhi-bo , Chen Zhi-wei , Zheng Sheng , Zhang Rui , Luo Xiao-yu
The study systematically analyzes the correlation between infrared dust bubbles and CO molecular gas in the Galactic region where 10 20 and 5, based on infrared survey data from WISE (Wide-Field Infrared Survey Explorer), GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire), and MIPSGAL (Multiband Imaging Photometer for Spitzer Galactic), combined with CO molecular gas survey data from the Milky Way Imaging Scroll Painting. A data analysis method based on Gaussian process regression was designed for the study. Among the 143 published infrared dust bubble samples, 44 bubbles were found to correlate with CO molecular gas, accounting for 30.8% of the total sample size. The study estimates the physical parameters such as CO molecular optical depth, H column density, and mass associated with bubbles, and conducts statistical analysis. The average column density of the 44 bubbles is calculated to be approximately 10 cm, with most bubble masses not exceeding 10 . The H column density of the molecular gas associated with the infrared dust bubbles generally reached the conditions for dense clumps that could potentially form stars. There are 26 bubbles that may be expanding, with an average expansion velocity of 2.75 km. The research results provide samples for understanding infrared dust bubbles and star formation studies.
{"title":"Correlation Study between Infrared Dust Bubbles and CO Molecular Gas in the Milky Way","authors":"Zeng Shu-guang , Zhang Jun-jie , Huang Yao , Liu De-jian , Zhang Peng , Jiang Zhi-bo , Chen Zhi-wei , Zheng Sheng , Zhang Rui , Luo Xiao-yu","doi":"10.1016/j.chinastron.2026.02.004","DOIUrl":"10.1016/j.chinastron.2026.02.004","url":null,"abstract":"<div><div>The study systematically analyzes the correlation between infrared dust bubbles and CO molecular gas in the Galactic region where 10<span><math><msup><mrow></mrow><mo>∘</mo></msup></math></span> <span><math><mrow><mo>≤</mo><mi>l</mi><mo>≤</mo></mrow></math></span> 20<span><math><msup><mrow></mrow><mo>∘</mo></msup></math></span> and <span><math><mrow><mo>|</mo><mi>b</mi><mo>|</mo><mo>≤</mo></mrow></math></span> 5<span><math><msup><mrow></mrow><mo>∘</mo></msup></math></span>, based on infrared survey data from WISE (Wide-Field Infrared Survey Explorer), GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire), and MIPSGAL (Multiband Imaging Photometer for Spitzer Galactic), combined with CO molecular gas survey data from the Milky Way Imaging Scroll Painting. A data analysis method based on Gaussian process regression was designed for the study. Among the 143 published infrared dust bubble samples, 44 bubbles were found to correlate with CO molecular gas, accounting for 30.8% of the total sample size. The study estimates the physical parameters such as CO molecular optical depth, H<span><math><msub><mrow></mrow><mn>2</mn></msub></math></span> column density, and mass associated with bubbles, and conducts statistical analysis. The average column density of the 44 bubbles is calculated to be approximately 10<span><math><msup><mrow></mrow><mn>22</mn></msup></math></span> cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></math></span>, with most bubble masses not exceeding 10<span><math><msup><mrow></mrow><mn>5</mn></msup></math></span> <span><math><msub><mi>M</mi><mo>⊙</mo></msub></math></span>. The H<span><math><msub><mrow></mrow><mn>2</mn></msub></math></span> column density of the molecular gas associated with the infrared dust bubbles generally reached the conditions for dense clumps that could potentially form stars. There are 26 bubbles that may be expanding, with an average expansion velocity of 2.75 km<span><math><mrow><mo>·</mo><msup><mi>s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>. The research results provide samples for understanding infrared dust bubbles and star formation studies.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 93-111"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453952","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}
As the number of mega-constellations increases, maneuver detection of non-cooperative satellites becomes an important part of Space Situational Awareness (SSA). The nonsingular thrust-Fourier coefficients (NSTFC) model can effectively fit the maneuvers of mega-constellations, but the feasibility of the online maneuver detection method based on this model needs to be verified. The method uses the orbital variations estimated by a filter as the classification attributes and uses the Naive Bayes as the classifier. The calculation results based on simulation show that this method can effectively identify three classes of space events: no maneuver, orbit raising, and orbit descending. The Macro score of classification can reach as high as 97.1%. The verification shows that this method may help improve the efficiency and accuracy of maneuver detection in the cataloging.
{"title":"Online Maneuver Detection of Non-cooperative Mega-constellations","authors":"Zhang Ji-dan , Zhu Ting-lei , Zhao Chang-yin , Liu Ai-rong","doi":"10.1016/j.chinastron.2026.02.008","DOIUrl":"10.1016/j.chinastron.2026.02.008","url":null,"abstract":"<div><div>As the number of mega-constellations increases, maneuver detection of non-cooperative satellites becomes an important part of Space Situational Awareness (SSA). The nonsingular thrust-Fourier coefficients (NSTFC) model can effectively fit the maneuvers of mega-constellations, but the feasibility of the online maneuver detection method based on this model needs to be verified. The method uses the orbital variations estimated by a filter as the classification attributes and uses the Naive Bayes as the classifier. The calculation results based on simulation show that this method can effectively identify three classes of space events: no maneuver, orbit raising, and orbit descending. The Macro <span><math><msub><mi>F</mi><mn>1</mn></msub></math></span> score of classification can reach as high as 97.1%. The verification shows that this method may help improve the efficiency and accuracy of maneuver detection in the cataloging.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 172-199"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453947","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.002
Liu Yan-jie , Zhao Hai-bin
Small solar system bodies with perihelion distances less than 0.307 AU/66 are known as near-Sun small bodies, and the extreme solar heating and high-temperature magnetized plasma environments they experience can reveal information about the small bodies themselves and contribute to the understanding of the near-solar space environment. Solar satellites have obtained a large amount of measured data of near-Sun small bodies, which provide opportunities for the study of the physical characterization and evolutionary history of different groups of near-Sun comets and asteroids, as well as the comparative study of the characteristics of extreme near-Sun comets (e.g., the Kreutz group) with those of other comets. Meanwhile, the observation of the coma and tail structure of near-Sun comets provides important references for the study of coronal properties such as the magnetic field structure of the solar system space, the velocity distribution of the solar wind, the coronal electron density, and the proton temperature. This article reviews the research progress made in the observation and in-situ exploration of near-Sun small bodies by solar satellites such as SOHO, STEREO, PSP, and SolO over the past 30 years, and introduces the corresponding research methods and technical methods. Finally, the article looks forward to the prospects and development directions of current and future domestic and international space and ground-based telescope observations of near-Sun small bodies.
{"title":"Current Status of Observation and Research of Near-Sun Small Bodies","authors":"Liu Yan-jie , Zhao Hai-bin","doi":"10.1016/j.chinastron.2026.02.002","DOIUrl":"10.1016/j.chinastron.2026.02.002","url":null,"abstract":"<div><div>Small solar system bodies with perihelion distances less than 0.307 AU/66 <span><math><msub><mi>R</mi><mo>⊙</mo></msub></math></span> are known as near-Sun small bodies, and the extreme solar heating and high-temperature magnetized plasma environments they experience can reveal information about the small bodies themselves and contribute to the understanding of the near-solar space environment. Solar satellites have obtained a large amount of measured data of near-Sun small bodies, which provide opportunities for the study of the physical characterization and evolutionary history of different groups of near-Sun comets and asteroids, as well as the comparative study of the characteristics of extreme near-Sun comets (e.g., the Kreutz group) with those of other comets. Meanwhile, the observation of the coma and tail structure of near-Sun comets provides important references for the study of coronal properties such as the magnetic field structure of the solar system space, the velocity distribution of the solar wind, the coronal electron density, and the proton temperature. This article reviews the research progress made in the observation and in-situ exploration of near-Sun small bodies by solar satellites such as SOHO, STEREO, PSP, and SolO over the past 30 years, and introduces the corresponding research methods and technical methods. Finally, the article looks forward to the prospects and development directions of current and future domestic and international space and ground-based telescope observations of near-Sun small bodies.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 40-75"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453953","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.009
Li Gen , Li Ying , Li Qiao , Li Hui
<div><div>The Ly<span><math><mi>α</mi></math></span> Solar Telescope (LST) is one of the payloads on board the Advanced Space-Based Solar Observatory (ASO-S, also known as <span><math><mrow><mi>K</mi><mi>u</mi><mi>a</mi><mi>f</mi><mi>u</mi></mrow></math></span>-1) mission, which consists of three scientific instruments: a White-light Solar Telescope (WST), a Solar Disk Imager (SDI), and a Solar Corona Imager (SCI). Both WST and SDI have a field of view of 1.2 <span><math><msub><mi>R</mi><mo>⊙</mo></msub></math></span> (<span><math><msub><mi>R</mi><mo>⊙</mo></msub></math></span> represents the solar radius and the full field of view spans 38.4<span><math><msup><mrow></mrow><mo>′</mo></msup></math></span>) and operate in the 360<span><math><mo>±</mo></math></span>2 nm (near white light) and 121.6<span><math><mo>±</mo></math></span>4.5 nm (i.e., Ly<span><math><mi>α</mi></math></span>) wavebands, respectively. Using imaging data from WST and SDI, we can explore the dynamics and evolution of solar activities in the lower atmosphere (from the photosphere to transition region), for example, to study the triggering mechanisms of solar flares, the physical properties of white-light flares, and the morphology evolution and kinematics of erupting filaments/prominences, as well as to derive physical parameters of the solar atmosphere. To obtain the physical parameters of different features in the solar atmosphere observed by WST and SDI, such as energy of flares and temperature and density of prominences, it is essential to convert the digital number (DN) of their observations into physical units (e.g., erg <span><math><mo>·</mo></math></span> cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></math></span> <span><math><mo>·</mo></math></span> s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> <span><math><mo>·</mo></math></span> sr<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>) through a process known as radiometric calibration. Radiometric calibration is a necessary step in the production of scientific data from WST and SDI. Currently, we perform in-flight radiometric calibrations of WST and SDI using the Sun as a reference source. For WST, we utilize solar spectral data released by the American Society of Testing and Materials (ASTM) in 2020, while for SDI we use the Extreme Ultraviolet Sensors (EUVS) aboard the Geostationary Operational Environmental Satellite R (GOES-R). In this paper, we provide the in-flight radiometric calibration factors and their uncertainties for WST and SDI during the normal observation period from August 2023 to February 2024. Furthermore, an empirical expression for the WST in-flight radiometric calibration factors is derived by fitting the daily averages of these coefficients. By utilizing the radiometric calibrated data, we can calculate the energy radiated by solar flares in both the near-white-light and Ly<span><math><mi>α</mi>
{"title":"In-flight Radiometric Calibrations of WST and SDI","authors":"Li Gen , Li Ying , Li Qiao , Li Hui","doi":"10.1016/j.chinastron.2026.02.009","DOIUrl":"10.1016/j.chinastron.2026.02.009","url":null,"abstract":"<div><div>The Ly<span><math><mi>α</mi></math></span> Solar Telescope (LST) is one of the payloads on board the Advanced Space-Based Solar Observatory (ASO-S, also known as <span><math><mrow><mi>K</mi><mi>u</mi><mi>a</mi><mi>f</mi><mi>u</mi></mrow></math></span>-1) mission, which consists of three scientific instruments: a White-light Solar Telescope (WST), a Solar Disk Imager (SDI), and a Solar Corona Imager (SCI). Both WST and SDI have a field of view of 1.2 <span><math><msub><mi>R</mi><mo>⊙</mo></msub></math></span> (<span><math><msub><mi>R</mi><mo>⊙</mo></msub></math></span> represents the solar radius and the full field of view spans 38.4<span><math><msup><mrow></mrow><mo>′</mo></msup></math></span>) and operate in the 360<span><math><mo>±</mo></math></span>2 nm (near white light) and 121.6<span><math><mo>±</mo></math></span>4.5 nm (i.e., Ly<span><math><mi>α</mi></math></span>) wavebands, respectively. Using imaging data from WST and SDI, we can explore the dynamics and evolution of solar activities in the lower atmosphere (from the photosphere to transition region), for example, to study the triggering mechanisms of solar flares, the physical properties of white-light flares, and the morphology evolution and kinematics of erupting filaments/prominences, as well as to derive physical parameters of the solar atmosphere. To obtain the physical parameters of different features in the solar atmosphere observed by WST and SDI, such as energy of flares and temperature and density of prominences, it is essential to convert the digital number (DN) of their observations into physical units (e.g., erg <span><math><mo>·</mo></math></span> cm<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>2</mn></mrow></msup></math></span> <span><math><mo>·</mo></math></span> s<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span> <span><math><mo>·</mo></math></span> sr<span><math><msup><mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></math></span>) through a process known as radiometric calibration. Radiometric calibration is a necessary step in the production of scientific data from WST and SDI. Currently, we perform in-flight radiometric calibrations of WST and SDI using the Sun as a reference source. For WST, we utilize solar spectral data released by the American Society of Testing and Materials (ASTM) in 2020, while for SDI we use the Extreme Ultraviolet Sensors (EUVS) aboard the Geostationary Operational Environmental Satellite R (GOES-R). In this paper, we provide the in-flight radiometric calibration factors and their uncertainties for WST and SDI during the normal observation period from August 2023 to February 2024. Furthermore, an empirical expression for the WST in-flight radiometric calibration factors is derived by fitting the daily averages of these coefficients. By utilizing the radiometric calibrated data, we can calculate the energy radiated by solar flares in both the near-white-light and Ly<span><math><mi>α</mi>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 200-214"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453946","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.006
Kang Kai-feng , Lin Jun
Using the high-resolution data in the TiO band taken by the 1 m New Vacuum Solar Telescope (NVST) at the Fuxian Lake Solar Observatory (FSO), we statistically investigated the effects of different magnetic field structures within the photosphere on granules via the newly developed algorithms for identifying granules. The data of NVST have much higher contrast (9.6%), therefore which is helpful for identifying smaller granules and performing more detailed analyses and studies than before. It is found that two critical scales of granules, D1 and D2, exist, and that the probability density of the equivalent diameter of granules with scales smaller than D1 follows a power law distribution similar to the Kolmogorov spectrum. We classify granules into three groups of different origins: the granules smaller than D1 are turbulent, those larger than D2 are convective, and those with scales between D1 and D2 result from blending of turbulence and convection, which is an intermediate case of the two formers. Meanwhile, we also noticed that the different magnetic field structures within the photosphere impact the critical scale, D1, of the turbulent granule in an apparent way such that the stronger the nearby magnetic field is, the smaller the value of D1 is. On the other hand, magnetic field imposes almost no effect on the mean radiative intensity of its external granules and the corresponding distribution features.
{"title":"Effects of Different Magnetic Structures within the Photosphere on Granulation","authors":"Kang Kai-feng , Lin Jun","doi":"10.1016/j.chinastron.2026.02.006","DOIUrl":"10.1016/j.chinastron.2026.02.006","url":null,"abstract":"<div><div>Using the high-resolution data in the TiO band taken by the 1 m New Vacuum Solar Telescope (NVST) at the Fuxian Lake Solar Observatory (FSO), we statistically investigated the effects of different magnetic field structures within the photosphere on granules via the newly developed algorithms for identifying granules. The data of NVST have much higher contrast (9.6%), therefore which is helpful for identifying smaller granules and performing more detailed analyses and studies than before. It is found that two critical scales of granules, D1 and D2, exist, and that the probability density of the equivalent diameter of granules with scales smaller than D1 follows a power law distribution similar to the Kolmogorov spectrum. We classify granules into three groups of different origins: the granules smaller than D1 are turbulent, those larger than D2 are convective, and those with scales between D1 and D2 result from blending of turbulence and convection, which is an intermediate case of the two formers. Meanwhile, we also noticed that the different magnetic field structures within the photosphere impact the critical scale, D1, of the turbulent granule in an apparent way such that the stronger the nearby magnetic field is, the smaller the value of D1 is. On the other hand, magnetic field imposes almost no effect on the mean radiative intensity of its external granules and the corresponding distribution features.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 130-149"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453948","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.001
Shen Fang , Lian Wan-yi , Tao Xin-yi
Solar energetic particle (SEP) events, driven by solar flares or coronal mass ejections (CMEs), can rapidly produce particles with energies from a few keV to several GeV. Their propagation is strongly modulated by the large-scale structure of the solar wind, posing risks to spacecraft operations and making SEPs a central target of space weather forecasting. In this work, we simulate SEP events by coupling the focused transport equation with multiple background solar wind models, perform a detailed parameter study, and reproduce several SEP events associated with stream interaction regions (SIRs) using observational constraints. Our results demonstrate that magnetic focusing is the dominant mechanism responsible for flux enhancement, whereas adiabatic cooling governs the decay phase in fast solar wind environments. Variations in solar wind parameters modify the width of corotating interaction regions (CIRs), which in turn lead to pronounced spatiotemporal variations in particle transport. Incorporating perpendicular diffusion effectively reconciles discrepancies among multi spacecraft flux profiles. This study establishes a comprehensive framework for understanding how large scale solar wind structures modulate SEP propagation. Future work should integrate multi mission observations to better capture CME driven shocks and thereby improve predictive capabilities for energetic particle transport.
{"title":"Progress in Simulations of Solar Energetic Particles Propagation in Large-scale Structures of Interplanetary Background Solar Wind","authors":"Shen Fang , Lian Wan-yi , Tao Xin-yi","doi":"10.1016/j.chinastron.2026.02.001","DOIUrl":"10.1016/j.chinastron.2026.02.001","url":null,"abstract":"<div><div>Solar energetic particle (SEP) events, driven by solar flares or coronal mass ejections (CMEs), can rapidly produce particles with energies from a few keV to several GeV. Their propagation is strongly modulated by the large-scale structure of the solar wind, posing risks to spacecraft operations and making SEPs a central target of space weather forecasting. In this work, we simulate SEP events by coupling the focused transport equation with multiple background solar wind models, perform a detailed parameter study, and reproduce several SEP events associated with stream interaction regions (SIRs) using observational constraints. Our results demonstrate that magnetic focusing is the dominant mechanism responsible for flux enhancement, whereas adiabatic cooling governs the decay phase in fast solar wind environments. Variations in solar wind parameters modify the width of corotating interaction regions (CIRs), which in turn lead to pronounced spatiotemporal variations in particle transport. Incorporating perpendicular diffusion effectively reconciles discrepancies among multi spacecraft flux profiles. This study establishes a comprehensive framework for understanding how large scale solar wind structures modulate SEP propagation. Future work should integrate multi mission observations to better capture CME driven shocks and thereby improve predictive capabilities for energetic particle transport.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 1-39"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453950","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.010
Pu Zheng-wei , Zhong Wei-ye , Shen Ming , Yan Zhuo-ying
This paper presents the design of a miniaturized ultra-wideband feed horn, which adopts an open-boundary quad-ridged horn structure. The backshort cavity at the feeding section is inspired by the Vivaldi antenna's reflective cavity design. By enlarging the cavity, the circulation path for surface currents at low frequencies is extended, which improves low-frequency radiation performance, thereby achieving a reduction in size. Compared to conventional quad-ridged horns, the proposed design reduces the size by approximately two-thirds to , where is the wavelength at the lowest operating frequency. The ultra-wideband feed operates at 2.2 – 16 GHz. Test results indicate that, besides a deviation near 6 GHz caused by assembling errors, the reflection coefficients at both ports remain below –8 dB across the entire operating band. Simulated results show that the aperture efficiency of the antenna exceeds 40% throughout the operating bandwidth. This feed horn is suitable for space science applications with strict requirements on size and weight.
{"title":"A Design of Miniaturized Ultra-wideband Feed Horn for Radio Astronomy Applications","authors":"Pu Zheng-wei , Zhong Wei-ye , Shen Ming , Yan Zhuo-ying","doi":"10.1016/j.chinastron.2026.02.010","DOIUrl":"10.1016/j.chinastron.2026.02.010","url":null,"abstract":"<div><div>This paper presents the design of a miniaturized ultra-wideband feed horn, which adopts an open-boundary quad-ridged horn structure. The backshort cavity at the feeding section is inspired by the Vivaldi antenna's reflective cavity design. By enlarging the cavity, the circulation path for surface currents at low frequencies is extended, which improves low-frequency radiation performance, thereby achieving a reduction in size. Compared to conventional quad-ridged horns, the proposed design reduces the size by approximately two-thirds to <span><math><mrow><mn>0.45</mn><msub><mi>λ</mi><mn>0</mn></msub><mo>×</mo><mn>0.45</mn><msub><mi>λ</mi><mn>0</mn></msub><mo>×</mo><mn>0.35</mn><msub><mi>λ</mi><mn>0</mn></msub></mrow></math></span>, where <span><math><msub><mi>λ</mi><mn>0</mn></msub></math></span> is the wavelength at the lowest operating frequency. The ultra-wideband feed operates at 2.2 – 16 GHz. Test results indicate that, besides a deviation near 6 GHz caused by assembling errors, the reflection coefficients at both ports remain below –8 dB across the entire operating band. Simulated results show that the aperture efficiency of the antenna exceeds 40% throughout the operating bandwidth. This feed horn is suitable for space science applications with strict requirements on size and weight.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 215-228"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453954","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}
Stars form through the gravitational collapse of dense molecular cores. Studying where this collapse motion is more likely to occur in molecular clumps will help to understand the formation of stars in various parts of molecular clumps and provide more information for studying star formation. We leverage CO data from the Milky Way Imaging Scroll Painting project, along with basic information on 3533 infall candidates identified via CO spectral lines, to search for the molecular clumps associated with these candidates and investigate the spatial distribution of infall candidates within them. By comparing the distributions obtained by scattering points at a series of certain number densities in a 3D sphere with the real distribution of infall candidates in molecular clumps, we observe that the distribution number density of infall candidates within molecular clumps approximately exhibits Gaussian decay with normalized center distance. Specifically, the relationship between the number density n of infall candidates and their normalized center distance r is , where a is the decay coefficient. In CO clumps, the best-fitting number density function is , while in CO clumps, it is . The results indicate that infall is more likely to occur in the center of molecular cloud clumps, and less likely to occur at the edges of the clumps
{"title":"Spatial Distribution of Infall Candidates in Molecular Clumps","authors":"Wan Yu-jie , Jiang Zhi-bo , Jiang Yu , Chen Zhi-wei","doi":"10.1016/j.chinastron.2026.02.003","DOIUrl":"10.1016/j.chinastron.2026.02.003","url":null,"abstract":"<div><div>Stars form through the gravitational collapse of dense molecular cores. Studying where this collapse motion is more likely to occur in molecular clumps will help to understand the formation of stars in various parts of molecular clumps and provide more information for studying star formation. We leverage CO data from the Milky Way Imaging Scroll Painting project, along with basic information on 3533 infall candidates identified via CO spectral lines, to search for the molecular clumps associated with these candidates and investigate the spatial distribution of infall candidates within them. By comparing the distributions obtained by scattering points at a series of certain number densities in a 3D sphere with the real distribution of infall candidates in molecular clumps, we observe that the distribution number density of infall candidates within molecular clumps approximately exhibits Gaussian decay with normalized center distance. Specifically, the relationship between the number density <em>n</em> of infall candidates and their normalized center distance <em>r</em> is <span><math><mrow><mi>n</mi><mo>∝</mo><msup><mi>e</mi><mrow><mo>−</mo><mi>a</mi><msup><mi>r</mi><mn>2</mn></msup></mrow></msup></mrow></math></span>, where <em>a</em> is the decay coefficient. In <span><math><msup><mrow></mrow><mn>13</mn></msup></math></span>CO clumps, the best-fitting number density function is <span><math><mrow><mi>n</mi><mo>∝</mo><msup><mi>e</mi><mrow><mo>−</mo><mn>4.5</mn><msup><mi>r</mi><mn>2</mn></msup></mrow></msup></mrow></math></span>, while in C<span><math><msup><mrow></mrow><mn>18</mn></msup></math></span>O clumps, it is <span><math><mrow><mi>n</mi><mo>∝</mo><msup><mi>e</mi><mrow><mo>−</mo><mn>3.2</mn><msup><mi>r</mi><mn>2</mn></msup></mrow></msup></mrow></math></span>. The results indicate that infall is more likely to occur in the center of molecular cloud clumps, and less likely to occur at the edges of the clumps</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 76-92"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453955","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.005
Chen Lin-fei , Xu Xin , Tian Jie , Zhi Qi-jun
The PSR J0934-5249 has been conducted in detail. The observational results show that this pulsar has both pulse nulling and subpulse drifting phenomena. Initially, the pulsar's pulse nulling phenomenon is investigated, successfully separating null pulses and burst pulses, and the NF (Nulling Fraction) is calculated to be 6.3% 0.4%, and the durations of both null and burst pulses are obtained. The results show that the longest duration of burst pulses is more than 150 pulse periods, while the duration of null pulses is no more than 4 pulse periods. In addition, this pulsar shows a quasi-periodic nulling phenomenon with a periodic value of approximately 33 pulse periods. Furthermore, analysis using longitude-resolved fluctuation spectra and two-dimensional fluctuation spectra reveals the presence of a clear subpulse drifting phenomenon in PSR J0934-5249. The vertical separation of the drift bands is calculated as (P is the rotation period of this pulsar). The horizontal separation of the drift bands is . Finally, polarization information for PSR J0934-5249 at a frequency of 1369 MHz is given. It is found that the pulsar's polarization position angle is consistent with the rotating vector model, and the observational geometry of the pulsar is well constrained based on kinematic effects.
{"title":"The Radiative Properties of PSR J0934-5249","authors":"Chen Lin-fei , Xu Xin , Tian Jie , Zhi Qi-jun","doi":"10.1016/j.chinastron.2026.02.005","DOIUrl":"10.1016/j.chinastron.2026.02.005","url":null,"abstract":"<div><div>The PSR J0934-5249 has been conducted in detail. The observational results show that this pulsar has both pulse nulling and subpulse drifting phenomena. Initially, the pulsar's pulse nulling phenomenon is investigated, successfully separating null pulses and burst pulses, and the NF (Nulling Fraction) is calculated to be 6.3% <span><math><mo>±</mo></math></span> 0.4%, and the durations of both null and burst pulses are obtained. The results show that the longest duration of burst pulses is more than 150 pulse periods, while the duration of null pulses is no more than 4 pulse periods. In addition, this pulsar shows a quasi-periodic nulling phenomenon with a periodic value of approximately 33 pulse periods. Furthermore, analysis using longitude-resolved fluctuation spectra and two-dimensional fluctuation spectra reveals the presence of a clear subpulse drifting phenomenon in PSR J0934-5249. The vertical separation of the drift bands is calculated as <span><math><mrow><msub><mi>P</mi><mn>3</mn></msub><mo>=</mo><mn>3.85</mn><mi>P</mi><mo>±</mo><mn>0.03</mn><mi>P</mi></mrow></math></span> (<em>P</em> is the rotation period of this pulsar). The horizontal separation of the drift bands is <span><math><mrow><msub><mi>P</mi><mn>2</mn></msub><mo>=</mo><mn>5</mn><mo>.</mo><msup><mn>2</mn><mo>∘</mo></msup><mo>±</mo><mn>1</mn><mo>.</mo><msup><mn>0</mn><mo>∘</mo></msup></mrow></math></span>. Finally, polarization information for PSR J0934-5249 at a frequency of 1369 MHz is given. It is found that the pulsar's polarization position angle is consistent with the rotating vector model, and the observational geometry of the pulsar is well constrained based on kinematic effects.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 112-129"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453956","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}
Pub Date : 2026-01-01Epub Date: 2026-03-13DOI: 10.1016/j.chinastron.2026.02.007
Feng Fu-yang, Li Zheng-xiang
Since the development of planetary science, more than 5000 exoplanets have been discovered. Understanding the evolution of protoplanetary disks is essential to clarify the classification of exoplanets and improve the efficiency of exoplanet detection. At the same time, exoplanet observations can be used to constrain and examine the physical parameters of the interaction between the protoplanetary disk and the planet. Therefore, in this paper, the surface density of the protoplanetary disk is linked to the star mass, combined with the distribution of exoplanet properties, and the interaction process between planets with different masses and specific protoplanetary disks is simulated by using the fluid dynamics code FARGO3D. Simulation results show that: (1) there is a power-law relationship between the relative surface density of the gap structure and the mass of the planet, and the power-law exponent has a strong correlation with the mass of the star; (2) there is a power-law relationship between the duration of the gap structure and the mass of the planet, and the power-law exponent has a weak correlation with the mass of the star; (3) there is a log-linear relationship between the width of the gap structure and the mass of the planet, and the power-law exponent has a weak correlation with the mass of the star. That is, the strength of the interaction between the planet and the protoplanetary disk is not only reflected in the relative surface density of the gap structure in the stable state, but also in the duration and width of the gap structure.
{"title":"Simulation of the Interaction between Planet and Protoplanetary Disk Based on FARGO3D","authors":"Feng Fu-yang, Li Zheng-xiang","doi":"10.1016/j.chinastron.2026.02.007","DOIUrl":"10.1016/j.chinastron.2026.02.007","url":null,"abstract":"<div><div>Since the development of planetary science, more than 5000 exoplanets have been discovered. Understanding the evolution of protoplanetary disks is essential to clarify the classification of exoplanets and improve the efficiency of exoplanet detection. At the same time, exoplanet observations can be used to constrain and examine the physical parameters of the interaction between the protoplanetary disk and the planet. Therefore, in this paper, the surface density of the protoplanetary disk is linked to the star mass, combined with the distribution of exoplanet properties, and the interaction process between planets with different masses and specific protoplanetary disks is simulated by using the fluid dynamics code FARGO3D. Simulation results show that: (1) there is a power-law relationship between the relative surface density of the gap structure and the mass of the planet, and the power-law exponent has a strong correlation with the mass of the star; (2) there is a power-law relationship between the duration of the gap structure and the mass of the planet, and the power-law exponent has a weak correlation with the mass of the star; (3) there is a log-linear relationship between the width of the gap structure and the mass of the planet, and the power-law exponent has a weak correlation with the mass of the star. That is, the strength of the interaction between the planet and the protoplanetary disk is not only reflected in the relative surface density of the gap structure in the stable state, but also in the duration and width of the gap structure.</div></div>","PeriodicalId":35730,"journal":{"name":"Chinese Astronomy and Astrophysics","volume":"50 1","pages":"Pages 150-171"},"PeriodicalIF":0.0,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147453949","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}
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