The Satellites of Pluto

Details about the 4 moons of Kuiper Belt Object, Pluto

Name	Diameter(s) (km)	Mean Distance From Planet (×10³ km)	Rotational Period (days)	Orbital Period (days)	Orbital Inclination	Albedo (%)
Charon	1,186	19.6	6.38725	6.38725	0°	50
Nix	~56	~48			0°
Hydra	~48	~64			0°
P4	13 - 34			31	0°

Name

Pluto has four satellites, one close and large; the others smaller and more distant. The large satellite of Pluto is named after Charon, the boatman for Pluto, the god of the dead.

Diameter

Charon has 49% the diameter of Pluto, the largest ratio between a satellite and the body it orbits.

Rotational and Orbital Periods

Most satellites rotate in the same period as they revolve around the main body. This is called Synchronous Rotation and is caused by the strong tidal forces exerted by the main body on the satellite. Charon and Pluto both have synchronous rotation and revolution with each other.

Orbital Inclination

This is the angle of inclination of the satellite orbits compared to the main body's equatorial plane. Charon orbits in the same plane as Pluto's equator.

Orbital Eccentricity

The orbits of most objects in the Solar System are ellipses. This curve resembles a flattened circle. The eccentricity describes how much the ellipse differs from a circle. An orbit with an eccentricity of 0 is a circle. An orbit with an eccentricity of 1 would be an open curve called a parabola. Charon orbits Pluto in a circular orbit.

Albedo

This is the percentage of sunlight that is reflected by the satellites. Charon's icy surface is reflective.

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