English: The Pluto–Charon system. Charon's orbit around Pluto is shown in green. Pluto's orbit around the Pluto–Charon system barycentre is shown in red. This shows that Pluto orbits a point outside itself. This is why Pluto and Charon are sometimes considered to be a double dwarf planet. The four small satellites of the Pluto–Charon system, Styx, Nix, Kerberos, and Hydra, are not shown. The image is probably a side view rather than a top view.