Key Facts about Charon

About Charon:

• It is the largest of Pluto's five moons, about half the size of Pluto.
• It was discovered telescopically on June 22, 1978, by James W. Christy and Robert S. Harrington at the U.S. Naval Observatory station in Flagstaff, Arizona. 
• The moon was named for Charon, the ferryman of dead souls to the realm of Hades (the Greek counterpart of the Roman god Pluto) in Greek mythology.
• Charon is 754 miles (1,214 kilometers) across, and Pluto is about 1,400 miles wide.
• Its mass is more than one-tenth of Pluto’s mass.
• Since Charon is so large and massive with respect to Pluto– the two are sometimes referred to as a double dwarf planet system. 
• The distance between them is 12,200 miles (19,640 km).
• The same surfaces of Charon and Pluto always face each other, a phenomenon called mutual tidal locking.
• In addition, Charon always shows the same hemisphere to Pluto, because (like many other moons) its rotation period is identical to its orbital period.
• Charon orbits Pluto every 6.4 Earth days.