摘要
对Ｔｉｔａｎ、Ｒｈｅａ和Ｉａｐｅｔｕｓ由数值改进产生轨道，并拟合１９６７－１９８８年的４５１４个星对的照相观测以求改进自由参数。土星系的质量Ｍｓａ和形状参数Ｊ２，以及卫星的质量ｍＩａ，ｍＲｈ作为自由参数参加求解。归算得：Ｍｓａ＝１／３４９８．０±０．１４Ｍｓｕｎ（太阳质量）（２．８５８７８０×１０－４±０．０００１０），Ｊ２＝０．０１６４７３±０．０００１１０，ｍＩａ＝３．３５×１０－６Ｍｓａ，ｍＲｈ＝４．４４×１０－６Ｍｓａ。归算表明，由于选择了由Ｔｉｔａｎ、Ｒｈｅａ、Ｉａｐｅｔｕｓ组成的较合理的动力学系统进行数值积分和采用了不同星对（Ｉａｐｅｔｕｓ－Ｔｉｔａｎ，Ｒｈｅａ－Ｔｉｔａｎ）观测资料作拟合改进求解，其结果显然要好。由地面观测资料归算的结果也进一步证实了空间测量结果的可靠性。
The orbit of Titan、Rhea and Iapetus have been generated by numerical integration,and fitted to 4510 photographic observations of Iapetus-Titan,Rhea-Titan made in the period 1967-1988.The fits yields good determinations of the mass ratio Saturn/Sun (2.858780+0.00011)-4,the dynamical flattening J2 of Saturn (0.016473+0.00010),and the mass ratio Rhea/Saturn (4.44×10-4),Iapetus/Saturn (3.35×10-4).The good determination of J2 and Msa obtained in this paper indicates that the use of an appropriate dynamical system inclusive of Titan、Rhea、Iapetus,and the fits to the observations for different satellite-pair can give the better result.The consistency between the results from ground-based observation and from spacecraft radio-tracking data provides a useful confirmation for the solution from space-obser vation.
出处
《天文学报》
CSCD
北大核心
1994年第2期120-130,共11页
Acta Astronomica Sinica
基金
国家自然科学基金
天文委员会基金
