mountain profile Institute for Astronomy University of Hawaii

Planets

Maintained by LG

Pluto and its moons

Pluto is now known to have at least five moons, which David Tholen and his colleagues have been studying using the Hubble Space Telescope.

Each of the four outer small satellites of Pluto are in near resonance with the much larger innermost moon Charon. The resonalnces are aproximately: Styx 3:1,  Nix 4:1, Kerberos 5:1, and Hydra 6:1, The reason they are not in a perfect resonance is because Charon is massive relative to Pluto; it is effectively a binary system.

 

Pluto and its Moons

HST iimage of Pluto and four of its moons: Pluto and Charon are saturated while three of the outer satellites are circled.