Planetary geodesy

Abstract

This report will attempt to review progress in planetary geodesy during the past four years. We basically restrict the discussion to gravity, topography, rotation and their physical significance. The format has been kept flexible to accommodate the varied amount of information available for the different planets. The bibliography provided is representative but not exhaustive. In addition to previous quadrennial reports by Kaula [1975], Anderson [1975], Ferrari and Bills [1979], and Sjogren [1983], publications by Anderson [1974], Sjogren et al [1976], Phillips and Lambeck [1980], Stevenson [1982], Davies et al [1983, 1986] and Hubbard [1984] provide valuable background information. A summary table of important geodetic parameters is provided.

Love numbers of the moon and of the terrestrial planets

“…In order to compare with other researcher's results, using the six-layer lunar model constructed by Bills and Ferrari (1977) (simplified as BF-6) we completed also the same computation. For the model BF-6 the algorithm used in the determination of the values of p(r), Vp(r) and Vs(r) is based on a cubic spline.…”

“…Due to recent achievements in planetary geodesy, at present important geodetic parameters of these planets are provided with high accuracy (e.g., Bills and Synnott, 1987). The geodetic parameters of the terrestrial planets and the Moon adopted in this study can be found in Table II.…”

“…Bills and Ferrari (1977) constructed the lunar interior model and gave the profiles of the density, p(r), and seismic velocities, Vp(r) and Vs(r), for this model. Siegfried II andSolomon (1974), Zharkov (1983), and Johnston and Toks6z (1977) discussed the task involves the construction of internal structure models for Mercury, Venus, and Mars, respectively.…”

Mapping Worlds With Irregular Shapes

“…I note at the outset that the determination of such cartographically significant but essentially astronomical values as the rotation period and axis orientation, and the definition of cardinal directions and prime meridians, are outside the scope of this paper. The procedures are fully documented in the astronomical literature (e.g., Davies et al 1986Davies et al , 1994; a useful review is given by Bills and Synnott 1987).…”