CORRECTIONS AND NEW DEVELOPMENTS IN RIGID EARTH NUTATION THEORY .1. LUNISOLAR INFLUENCE INCLUDING INDIRECT PLANETARY EFFECTS

The tables of nutation as given by Kinoshita & Souchay (1990) have bee n constructed with use of the value of the general precession in longi tude as adopted by the IAU1976 (Lieske et al. 1977). The recent observ ations agree to give a correction of about 0.3 ''/cy. to this last val ue. Because of the interaction between the precession and the nutation for a rigid Earth model, it became necessary to use an updated value of p(A), that is to say: p(A) = 5028.7700 ''/cy and to recalculate the largest coefficients of nutation influenced by this change. This is o ne of the aim of this paper. Moreover, we study a new contribution to the nutation not included in the preceding studies, which are due to t he periodic oscillations of the ecliptic. We also calculate the planet ary tilt-effect on the nutation pointed out by Williams (1994), which was not included in Kinoshita & Souchay (1990). At last all the coeffi cients of the nutation for a rigid-Earth model have been recalculated, with an improved threshold of the potential (5 x 10(-10)). We give fi nal tables showing all the coefficients subject to some change with re spect to Kinoshita & Souchay (1990), for the lunisolar part, including the indirect planetary effects. Only the direct action of the planets on the nutation and the influence of the J(3) geopotential is not stu died here. They will be the subject of a next paper. At last a new val ue of the dynamical ellipticity of the Earth is calculated in the foll owing: H-D = 0.0032737548.