Major MoonMoon of Pluto
Charon
Pluto's largest moon, so big the pair forms a binary system.
1,212km
Diameter19,591km
From Pluto6.4days
Orbital Period1978
DiscoveredAbout
Charon is the largest moon of Pluto and is so large relative to Pluto that the two are often considered a binary system. The barycenter of their orbits lies between the two bodies. Charon has a reddish polar cap made of tholins processed from methane escaping Pluto's atmosphere.
Properties
1,212km
Diameter19,591km
Semi-major Axis6.39days
Orbital Period1.586e21kg
Mass1.70g/cm³
DensityYes
Tidally Locked1978
Discovery YearJames Christy
Discovered ByNotable Facts
01
Charon is so large relative to Pluto that the pair is often called a double dwarf planet
02
Its north pole has a reddish cap informally named Mordor Macula
03
Charon and Pluto are mutually tidally locked, always showing the same face to each other
04
The New Horizons mission revealed Charon has canyons, mountains, and a surprisingly varied surface