Determining the moment of inertia of triaxial Mars with updated global gravity models  

作　　者：ChangYi Xu Yan Jiang 

机构地区：[1]Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China

出　　处：《Earth and Planetary Physics》2023年第6期615-619,共5页地球与行星物理（英文版）

基　　金：supported by the National Key Research and Development Program (2022YFF0503200);the National Natural Science Foundation of China (42274114);the Key Program of the Institute of Geology and Geophysics, Chinese Academy of Sciences (IGGCAS-202102)

摘　　要：The principal moments of inertia(PMIs)with the principal axes are usually taken as the dynamic figure parameters of Mars;they can be deduced from satellite-observed degree-two gravitational potentials in recent global gravity models and from the dynamic ellipticities resulting from precession observations.These PMIs are natural and significant for the geodetic,geophysical,and geodynamic problems of Mars,which are functions of internal density distributions.In this study,a closed and concise formula for determining the PMIs of the entire planet and its core was developed based on the second invariants of gravity and a multipole expansion.We deduced the polar oblateness J^(2)and the equatorial ellipticity J_(22)of Mars to be 1.9566×10^(−3)and 6.3106×10^(−5),respectively.The preferred principal moments of inertia of Mars are A=2.66589×1036 kg·m^(2),B=2.66775×10^(36)kg·m^(2),and C=2.68125×10^(36)kg·m^(2).These values indicate that Mar is slightly triaxial.The equatorial principal moment of inertia of the Martian core is 1.46008×10^(35)kg·m^(2),accounting for~5.47%of the planet’s PMI;this result is critical for investigating the density and size of the core of Mars,and the planet’s free core nutation.

关 键 词：MARS principal moment of inertia dynamic ellipticity Chandler wobble core density and size 

分 类 号：P185.3[天文地球—天文学] V476.4[航空宇航科学与技术—飞行器设计]