Pluto's Moon: Charon

Pluto's Moon - Charon

C haron was named after the boatman in Greek mythology who operated the ferry across the River Styx to Pluto's realm in the underworld. Charon was discovered in 1978 by J. Christy. Its surface composition seems to be different from Pluto's. The moon appears to be covered with water ice rather than methane ice. Its orbit is gravitationally locked with Pluto, so both bodies always keep the same hemisphere facing each other. Very little is known about Charon, but in 2001 the Pluto Express space probes will be further studing Pluto and its moon.

PHYSICAL DATA FOR CHARON
Mass (kg)	1.77e + 21
Mass (Earth = 1)	2.9618e - 04
Radius (km)	635
Radius (Earth = 1)	9.9561e - 02
Mean Density (g/cm³)	1.83
Mean Distance from Jupiter (km)	19,640
Magnitude (V₀)	16.8

ORBITAL DATA FOR CHARON
Rotational period (days)	6.38725
Orbital period (days)	6.38725
Mean orbital velocity (km/s)	0.23
Orbital eccentricity	0.00
Orbital inclination (degrees)	98.80
Escape (km/s)	0.610
Albedo	0.5

Physical Data Key

Mass	Mass
Mass	Mass compared to that of Earth.
Radius	Radius
Radius	Radius compared to that of Earth.
Mean Density	Average Density.
Distance	Distance to the planet's center.
Magnitude	The brightness of a star or object.

Orbital Data Key

Rotational Period	Number of days to make one complete rotation.
Orbital Period	Number of days to obital the planet.
Mean Orbital Velocity	Average obital speed.
Orbital Eccentricity	Eccentricity.
Orbital Inclination	The tilt of the moon or planet.
Escape	Escape Velocity.
Albedo	Visual geometric albedo.