The SiTian project,with its vast field of view,will become an ideal platform for scientific research on asteroids.In this study,we develop a pipeline to analyze the photometry of asteroids and derive their periods fro...The SiTian project,with its vast field of view,will become an ideal platform for scientific research on asteroids.In this study,we develop a pipeline to analyze the photometry of asteroids and derive their periods from the data collected by the SiTian pathfinder project Mini-SiTian(MST).The pipeline is applied to the MST f02 region,an MST test region with a sky area of 2°.29×1°.53.Rotation periods of 22 asteroids are derived by the obtained light curve analysis.Among them,there are eight asteroids available in the Asteroid Lightcurve Photometry Database(ALCDEF),and six of them with more photometric points(>200)that have similar period parameters as the ones in ALCDEF.Additionally,the periods for 14 of these asteroids are newly obtained and are not listed in ALCDEF.This study demonstrates the feasibility of asteroid photometric research by the SiTian project.It shows that future observations from the SiTian project will provide even more photometry of asteroids,significantly increasing the number of available light curves.The potential vast photometric data on asteroids will help us to further understand the physics of asteroids,their material composition,and the formation and evolution of the solar system.展开更多
The perihelion of long-period comets places them near the Sun so they may exhibit activity.Before 2013 LU28 reached its perihelion,we performed a continuous observation to detect possible activity.Using the Lijiang 2....The perihelion of long-period comets places them near the Sun so they may exhibit activity.Before 2013 LU28 reached its perihelion,we performed a continuous observation to detect possible activity.Using the Lijiang 2.4 m telescope with a Johnson R filter,we measured the brightness of 2013 LU28 from 2024 January 3 to April 13.The instrumental magnitudes were subsequently transformed into the Pan-STARRS r system.Due to the noticeable descending trend in the absolute magnitude,we verified the cometary activity and constrained some photometric properties of 2013 LU28.Consequently,the increased cross-sectional area had a rate of 42.8 km^(2)day^(−1),and the corresponding mass-loss rate was 2.64 kg s^(−1)with the assumption of a dust-particle size a=10 mm and the densityρ=400 kg m^(−3).We estimated the nucleus radius as 0.11■r_(n)■0.21 km for CO sublimation and 0.20■r_(n)■0.71 km for CO_(2)sublimation and the grain size of 2013 LU28 was ac;117.95μm for CO and ac■7.57μm for CO_(2).The long-term observations provided in this paper will offer significant value for investigating the mechanisms driving the activity of 2013 LU28.展开更多
A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum di...A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum diameter of 1360 m.The bottom of the crater is filled by Quaternary sediments with large amounts of rock fragments underneath.The discovery of quartz planar deformation features in rock clasts on the crater floor provides diagnostic evidence for the impact origin of the structure.The shape of the crater is largely due to the impact having occurred on a ridge terrain.The impact event probably occurred in the late Cenozoic Era.The Hailin impact crater is the fourth confirmed Chinese impact crater.展开更多
基金supports from the National Natural Science Foundation of China(NSFC,grant Nos.12203002 and 11973015)supports from the National Key Basic R&D Program of China via 2023YFA1608303 and the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0550103)+6 种基金supports from the National Natural Science Foundation of China(NSFCgrant No.12373015)supports from the National Natural Science Foundation of China(NSFCgrant Nos.12120101003 and 12373010)National Key R&D Program of China(grant Nos.2023YFA1607800,2023YFA1607804,2022YFA1602902)Beijing Municipal Natural Science Foundation(grant No.1222028)Strategic Priority Research Program of the Chinese Academy of Science(grant Nos.XDB0550100 and XDB0550000).
文摘The SiTian project,with its vast field of view,will become an ideal platform for scientific research on asteroids.In this study,we develop a pipeline to analyze the photometry of asteroids and derive their periods from the data collected by the SiTian pathfinder project Mini-SiTian(MST).The pipeline is applied to the MST f02 region,an MST test region with a sky area of 2°.29×1°.53.Rotation periods of 22 asteroids are derived by the obtained light curve analysis.Among them,there are eight asteroids available in the Asteroid Lightcurve Photometry Database(ALCDEF),and six of them with more photometric points(>200)that have similar period parameters as the ones in ALCDEF.Additionally,the periods for 14 of these asteroids are newly obtained and are not listed in ALCDEF.This study demonstrates the feasibility of asteroid photometric research by the SiTian project.It shows that future observations from the SiTian project will provide even more photometry of asteroids,significantly increasing the number of available light curves.The potential vast photometric data on asteroids will help us to further understand the physics of asteroids,their material composition,and the formation and evolution of the solar system.
基金Funding for the telescope has been provided by CAS and the People’s Government of Yunnan Provincefunded by the Civil Aerospace pre-research project D020302+2 种基金National Natural Science Foundation of China (U12150009,12150009)the CAS Light of West China Programthe science research grants from the China Manned Space Project with NO.CMS-CSST-2021-B10
文摘The perihelion of long-period comets places them near the Sun so they may exhibit activity.Before 2013 LU28 reached its perihelion,we performed a continuous observation to detect possible activity.Using the Lijiang 2.4 m telescope with a Johnson R filter,we measured the brightness of 2013 LU28 from 2024 January 3 to April 13.The instrumental magnitudes were subsequently transformed into the Pan-STARRS r system.Due to the noticeable descending trend in the absolute magnitude,we verified the cometary activity and constrained some photometric properties of 2013 LU28.Consequently,the increased cross-sectional area had a rate of 42.8 km^(2)day^(−1),and the corresponding mass-loss rate was 2.64 kg s^(−1)with the assumption of a dust-particle size a=10 mm and the densityρ=400 kg m^(−3).We estimated the nucleus radius as 0.11■r_(n)■0.21 km for CO sublimation and 0.20■r_(n)■0.71 km for CO_(2)sublimation and the grain size of 2013 LU28 was ac;117.95μm for CO and ac■7.57μm for CO_(2).The long-term observations provided in this paper will offer significant value for investigating the mechanisms driving the activity of 2013 LU28.
基金financial support from the Shanghai Key Laboratory Novel Extreme Condition Materials,China(Grant No.22dz2260800)the Shanghai Science and Technology Committee,China(Grant No.22JC1410300)。
文摘A uniquely shaped impact structure,the Hailin impact crater,has been discovered in northeast China.The crater was formed on a granodiorite hillside and is an oval depression with asymmetric rim height and a maximum diameter of 1360 m.The bottom of the crater is filled by Quaternary sediments with large amounts of rock fragments underneath.The discovery of quartz planar deformation features in rock clasts on the crater floor provides diagnostic evidence for the impact origin of the structure.The shape of the crater is largely due to the impact having occurred on a ridge terrain.The impact event probably occurred in the late Cenozoic Era.The Hailin impact crater is the fourth confirmed Chinese impact crater.
