应用天文研究组知识库

月球物理天平动是月球运动在空间的描述。确定月球物理天平动，可以推测物理天平动的激发与耗散机制，比如陨击、月震和核幔粘滞摩擦等，测定月球物理天平动对认识太阳系天体的起源、演化及结构等具有十分重要的意义。利用最新的INPOP19a历表数据，完成了对从历表提取的欧拉角到月球物理天平动的转换，得到的物理天平动数值分别与该系列历表INPOP17a以及DE430对比发现，不同历表的物理天平动之差存在稳定的周期。对比历表欧拉角的差别，计算出地心到月面反射器A15的距离最大有30 cm的差别，此结果对月球激光测距的预报精度有较大的影响，为后续高精度测月研究打下基础。研究结果表明，INPOP19a最为稳定，在月球物理天平动研究中推荐使用INPOP19a。

Lunar librations is a description of the movement of the moon in space. To determine the lunar librations makes it possible to speculate about the excitation and dissipation mechanisms of the libration, such as meteor strikes, moon earthquakes, and viscous friction between the core and mantle. Therefore, the determination of the lunar librations is useful for understanding the origin, evolution, and structure of celestial bodies in the solar system. During the research, the latest INPOP19a ephemeris data is used, the conversion of Euler angle extracted from the ephemeris to the lunar physical librations is completed. The numerical model of the physical librations is compared with the ephemeris INPOP17a and DE430. It is found that the difference in physical librations of different ephemerides has a stable period. It is calculated that there is a maximum difference of 30 cm between the center of the earth and the lunar reflector A15. This result has a greater impact on the prediction accuracy of the lunar laser ranging. It provides theoretical support for the high⁃precision lunar laser ranging. The results show that the accuracy of INPOP19a is significantly higher than INPOP17a and DE430, so INPOP19a is recommended in the research of lunar librations.