<P> There is minor debate over the preferred pronunciation of the name . The practice of following the classical pronunciation established for the mythological ferryman Charon (IPA (ˈkɛ: rən)) is used by major English - language dictionaries, such as the Merriam - Webster and Oxford English Dictionary . These indicate only one pronunciation of "Charon" when referring specifically to Pluto's moon: with an initial "k" sound . Speakers of many languages other than English, and many English - speaking astronomers as well, follow this pronunciation . </P> <P> However, Christy himself pronounced the ch as sh (IPA (ʃ)), after his wife Charlene . Because of this, as an acknowledgement of Christy and sometimes as an in - joke or shibboleth, the initial sh pronunciation is common among astronomers when speaking English, and this is the prescribed pronunciation at NASA and of the New Horizons team . </P> <P> Simulation work published in 2005 by Robin Canup suggested that Charon could have been formed by a collision around 4.5 billion years ago, much like Earth and the Moon . In this model, a large Kuiper belt object struck Pluto at high velocity, destroying itself and blasting off much of Pluto's outer mantle, and Charon coalesced from the debris . However, such an impact should result in an icier Charon and rockier Pluto than scientists have found . It is now thought that Pluto and Charon might have been two bodies that collided before going into orbit about each other . The collision would have been violent enough to boil off volatile ices like methane (CH) but not violent enough to have destroyed either body . The very similar density of Pluto and Charon implies that the parent bodies were not fully differentiated when the impact occurred . </P> <P> Charon and Pluto orbit each other every 6.387 days . The two objects are gravitationally locked to one another, so each keeps the same face towards the other . This is a case of mutual tidal locking, as compared to that of the Earth and the Moon, where the Moon always shows the same face to Earth, but not vice versa . The average distance between Charon and Pluto is 19,570 kilometres (12,160 mi). The discovery of Charon allowed astronomers to calculate accurately the mass of the Plutonian system, and mutual occultations revealed their sizes . However, neither indicated the two bodies' individual masses, which could only be estimated, until the discovery of Pluto's outer moons in late 2005 . Details in the orbits of the outer moons revealed that Charon has approximately 12% of the mass of Pluto . </P>

Where is charon located in the solar system