The origin of the Pluto-Charon system

Abstract

The formation conditions of the binary systems Pluto-Charon in the early solar nebula are analyzed with special emphasis on its high spin angular momentum, which would lead the system beyond the limit of rotational stability in the ideal case that both bodies coalesced into a single body. Among several possible scenarios of formation, the acquisition of such a high content angular momentum is explained on the basis of a collision of two protoplanets of comparable masses in an intermediate stage of the planetary formation, before Neptune perturbed Pluto on a highly eccentric orbit.