  The dynamical structure of the phase space of the Pluto--Charon system is
studied in the model of the spatial circular restricted three-body problem by
using numerical methods. With the newly discovered two small satellites S/2005
P1 and S/2005 P2, the Pluto--Charon system can be considered as the first known
binary system in which celestial bodies move in P-type orbits. It is shown that
the two satellites are in the stable region of the phase space and their origin
by capture is unlikely. Also the large mass parameter allows to regard the
satellites as a model of a new class of exoplanets orbiting around stellar
binary systems.

Astrophysics