Evolution of Subkilometer-scale Impact Craters on the Lunar Maria as Constrained from Mini-RF Data and Topographic Degradation Model  

作　　者：孙庆海 法文哲 祝梦华 都骏 Qinghai Sun;Wenzhe Fa;Meng-Hua Zhu;Jun Du(State Key Laboratory of Lunar and Planetary Sciences,Macao University of Science and Technology,Macao 999078,China;CNSA Macao Center for Space Exploration and Science,Macao 999078,China;Institute of Remote Sensing and Geographical Information System,School of Earth and Space Sciences,Peking University,Beijing 100871,China;State Key Laboratory of Space Weather,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]State Key Laboratory of Lunar and Planetary Sciences,Macao University of Science and Technology,Macao 999078,China [2]CNSA Macao Center for Space Exploration and Science,Macao 999078,China [3]Institute of Remote Sensing and Geographical Information System,School of Earth and Space Sciences,Peking University,Beijing 100871,China [4]State Key Laboratory of Space Weather,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Research in Astronomy and Astrophysics》2023年第12期19-33,共15页天文和天体物理学研究（英文版）

基　　金：supported by the Science and Technology Development Fund of Macao(0020/2021/A1,0079/2018/A2);National Key Research and Development(2019YFE0123300);the National Natural Science Foundation of China(12173004,41941002)。

摘　　要：Physical properties(e.g.,ejecta size and distribution)of impact craters are crucial and essential to understanding the ejecta excavation and deposition process,estimating rock breakdown rate,and revealing their evolution characteristics.However,whether these physical properties are scale-dependent and how they evolve in different radial regions needs further studies.In this study,we first investigated the physical properties and evolution of subkilometer(D≤800 m)craters on lunar maria based on the radar circular polarization ratio(CPR).In addition,we estimated the periods over which rocks and blocky ejecta are exposed and buried in the shallow subsurface layer(termed as exposure time)in different radial regions and assessed the retention time and degradation states for potential radar anomalous craters.We found that in the central region of craters,the largest median CPR occurs after an 80 Myr delay following crater formation.In the rim region,there is no obvious CPR peak in the first100 Ma,whereas in the upper wall region,an evident CPR peak occurs beyond 100 Ma and could last over one billion years.In addition,the probable exposure time of rocks and blocky ejecta is estimated to be~2.0 Gyr(central region),~2.7 Gyr(upper wall region),~2.1 Gyr(rim region),and~0.6 Gyr(continuous ejecta blanket region).We also propose that the retention time of radar anomalous craters depends on the crater size,whereas their degraded states are independent of crater size.

关 键 词：Moon-planets and satellites surfaces-planets and satellites physical evolution 

分 类 号：P184[天文地球—天文学]