Free and Forced Librations of Two-Layer Structure of the Moon

Abstract

Based on the lunar physical parameters in ephemeris DE430/LE430 of JPL/NASA, we estimated the moments of inertia of the Moon. Using these values of moment of inertia, the frequencies and periods of lunar free librations in different modes have been calculated by solving the rotational differential equations of rigid Moon. We compared the results and discussed the analytic results of lunar librations. Meanwhile, we also estimated the forced librations by means of the amplitude of longitudinal part. For the further research, more analytic methods should be mixed into numerical results, and the interactions between two layers would be next objective.

Keywords

lunar librations / analytic methods / frequencies and periods / amplitude