小行星(469219) Kamo`oalewa轨道的确定与误差分析

作为一颗与地球共轨道的小行星,(469219)Kamo'oalewa是一个具有很高研究价值的近地小天体,也是中国首次小行星探测计划的目标天体之一.针对其轨道特性,建立了兼顾太阳、地球和月球非球形引力作用的小行星动力学模型.并在该模型的基础上,利用国际小行星中心(Minor Planet Center,MPC)提供的2004|2018年间的光学观测数据对该小行星的轨道进行确定.拟合后观测残差的均方根误差约为0:2″(与美国喷气推进实验室的Horizons在线历表系统相当),其中2004年期间数据的观测残差有所改进.最后,对小行星(469219)Kamo'oalewa的轨道误差进行了详细分析,并预报了2020-2025年期间该小行星的轨道误差.

Orbit Determination of the Asteroid (469219) Kamo`oalewa and Its Error Analysis

As an Earth co-orbital asteroid, (469219) Kamo\`oalewa is a near earth object (NEO) with high value of research and one of the targets explored by the first Chinese asteroid exploration mission. Given its orbit characteristics, we build a refined dynamical model for this asteroid. In the model, figure effects induced by nonspherical gravitational fileds of the Sun, the Earth and the Moon are taken into account. On the basis of the dynamical model of the asteroid (469219) Kamo\`oalewa, its orbit is determined with optical data from 2004 to 2018 downloaded from the Minor Planet Center (MPC) database. The root mean square error of post-fit residuals is about 0.2 arc second (comparable with that of JPL/Horizons), and the post-fit residuals of optical observations in 2004 are decreased. At the end, we implement error analysis on the asteroid (469219) Kamo\`oalewa''s orbit in detail, and also predict its orbit error at the time interval between 2020 and 2025.