Passing through resonance: The excitation and dissipation of the lunar free libration in longitude
Planetary perturbation terms are considered that have small amplitudes, but whose periods are close to the resonant period of the lunar libration in longitude. It is shown that one of them with the amplitude only \(0.00021''\) could be source of the \(\sim 1''\) amplitude free libration, if the viscoelastic properties of the Moon are similar to those of the Earth.
scientific article; zbMATH DE number 486927