月球的力学形状以及月球物理参数的研究

利用月球重力场展开式中的Stokes系数,确定了月球的力学形状(月球水准而方程),然后计算了最佳拟合的月球椭球体的参数,周时,通过数值求解Clairaut方程获得了一组月球物理参数的流体静力学平衡值,进而讨论了月球形状参数中的非流体静力学分量的特点.显而易见,当选取月球的一些物理参数时,应考虑到地月系经历了潮汐演化这一事实,最后,建议把月球的物理参数分成三类初始常数,导出常数,以及估算常数(参看表4),本文给出了计算各导出常数的公式,并建议把月球的潮汐洛夫数k_2归于估算常数中,当前可用月球内部结构模型(例如本文的LUNA 91-04)的计算值(k_2=0.0266)作为其采用值,该值与IERS Standards(1992)中给出的数值(0.0222)不同;当k_2值改变吋,将会影响到导出常数C_(22)和C/MR~2的取值.

A STUDY OF DYNAMICAL FIGURE AND OF PHYSICAL PARAMETERS FOR THE MOON

Using the Stokes coefficients in gravitational field expansion of the Moon, we determined the lunar dynamical figure (selenoid), then calculated the parameters of triaxial best-fitting ellipsoid of the Moon. Moreover, we derived a set of hydrostatic values of lunar physical parameters by solving the Clairaut equation, and discussed the feature of nonhydrostatic components in the lunar figure parameters. Apparently, when we select some physical parameters of the Moon, it is necessary to consider the fact that the Earth-Moon system has been undergoing the tidal evolution. Finally, we suggest taht the lunar physical parameters can be divided into three kinds: primary constants, derived constants, and estimated constants (seeTable 4). We listed the formulae for calculating the derived constants, and suggest taht the tidal Love number, k_2, of the Moon belong to the estimated constants. At present, a value obtained from model calculations (e.g. LUNA 91-04 in this paper), k_2=0.0266, should be adopted. This value is different from that of k_2 in IERS Standards (1992). When the value of k2 changes, it will cause a variation of the values C_(22) and C/MR~2.