Clues to the origin of jupiter’s trojans: the libration amplitude distribution

We model with numerical algorithms the dynamical processes that possibly lead to the trapping of Jupiter’s Trojans from a primordial population of planetesimals orbiting nearby a proto-Jupiter. The predictions of models based on mutual planetesimal collisions and on the mass growth of Jupiter are compared with observations. In particular, we concentrate on the distribution of the libration amplitude. The two mechanisms for trapping reproduce closely the libration amplitude distribution of the real Trojans only when the long-term dynamical diffusion described by Levison et al. (1997, Nature 385, 42–44) is taken into account.