Pluto and Charon A Case of Precession-Orbit Resonance

by: Rubincam, D. P.

ABSTRACT

Pluto may be the only known case of precession-orbit resonance in the solar
system. Pluto's precession caused by Charon about their orbital plane might
have a period of 250.8 Earth years, the same as the orbital period of the
Pluto-Charon system about the Sun. A Pluto flyby mission might refute or
provide more evidence for the resonance. It is not clear how the planet
would get in to such a resonance. Present-day Earth-based is observations
appear to rule out Pluto's being in a resonance associated with half of
its orbital period about the Sun unless Pluto has a large nonhydrostatic
component to its flattening.

Goddard Space Flight Center, 1999, Document ID 19990080924