Here is an educational excerpt from wikipedia on the subject:

Orbital energies and orbit shapes

With two bodies, an orbit is a conic section. The orbit can be open (so the object never returns) or closed (returning), depending on the total energy (kinetic + potential energy) of the system. In the case of an open orbit, the speed at any position of the orbit is at least the escape velocity for that position, in the case of a closed orbit, always less. Since the kinetic energy is never negative, if the common convention is adopted of taking the potential energy as zero at infinite separation, the bound orbits have negative total energy, parabolic trajectories have zero total energy, and hyperbolic orbits have positive total energy.

We hope you like this cool video showing a planet with two suns!  And this decade has been incredible in terms of new discoveries from NASA, planetary surfaces and the like.

Check back too for more on the Ceres story as they get more images of the surface.

thanks to the washington post for the great info