Moons of Pluto moons orbit Pluto at two to four times the distance of Charon, ranging from Styx at 42,700 kilometres to Hydra at 64,800 kilometres from the barycenter of the system. They have nearly circular prograde orbits in the same orbital plane as Charon. All are much smaller than Charon. Nix and Hydra, the two larger, are roughly 42 and 55 kilometers on their longest axis respectively, and Styx and Kerberos are 7 and 12 kilometers respectively. All four are irregularly shaped. The Pluto system is highly compact and largely empty. Moons could potentially orbit Pluto at up to 53% (or 69%,
Tombaugh Regio the International Astronomical Union (IAU), together with names for 13 other surface features on Pluto. Some people find the feature also resembles the Disney character Pluto, an animated non-anthropomorphic dog which shares the name of the dwarf planet. The Walt Disney Company acknowledged this perceived likeness in a short animation. Tombaugh Regio Tombaugh Regio (), nicknamed The Heart after its shape, is the largest bright surface feature of the dwarf planet Pluto. It is just north of the equator, to the northeast of Cthulhu Macula and to the northwest of Krun Macula, which are both dark features. Its western lobe,