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CHARON

The largest moon of Pluto and one of the most unusual satellite systems in the Solar System.
THE GIANT MOON
Charon is Pluto's largest moon and is so large compared with Pluto that the two objects are often described as a double dwarf-planet system. Their shared centre of mass lies outside Pluto, meaning Pluto and Charon orbit around a point in space between them rather than Charon simply orbiting a completely stationary Pluto. Charon was discovered in 1978 by astronomer James Christy. The New Horizons spacecraft provided the first close-up observations of Charon during its historic Pluto flyby in 2015.
1,212 km
DIAMETER
6.39 DAYS
ORBITAL PERIOD
~19,640 km
DISTANCE FROM PLUTO
1978
DISCOVERED
1 : 2
PLUTO : CHARON DIAMETER RATIO
2015
FIRST CLOSE-UP IMAGES
A TRUE DOUBLE WORLD
Charon is much larger relative to its primary body than most major moons in the Solar System. Its diameter is roughly half that of Pluto, making Charon an enormous companion rather than a small satellite. Both Pluto and Charon are tidally locked to each other. This means the same side of Charon always faces Pluto, while the same side of Pluto always faces Charon. Charon's surface contains large canyons, mountains and a distinctive reddish polar region known as Mordor Macula. The moon's interior is believed to contain a mixture of rock and water ice.
CHARON FEATURES
DOUBLE SYSTEM
Charon and Pluto orbit a common barycenter located outside Pluto, making their system unusual among planetary satellites.
TIDALLY LOCKED
Charon and Pluto are mutually tidally locked, so each world always shows the same hemisphere to the other.
MORDOR MACULA
Charon's northern polar region has a dark reddish colour caused by complex surface materials.
DID YOU KNOW?
Charon is so large compared with Pluto that their centre of mass lies outside Pluto.
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