Puck (moon) - Physical Characteristics

Physical Characteristics

Puck is the largest of small inner moons of Uranus, which orbit inside the orbit of Miranda. It is intermediate in size between Portia (the second largest inner moon) and Miranda (the smallest of the five large classical moons). Puck's orbit is located between the rings of Uranus and Miranda. Little is known about Puck aside from its orbit, radius of about 81 km, and geometric albedo in the visible light of approximately 0.11.

Of the moons discovered by the Voyager 2 imaging team, only Puck was discovered early enough that the probe could be programmed to image it in some detail. Images showed that Puck has a shape of a slightly prolate spheroid (ratio between axes is 0.97 ± 0.04). Its surface is heavily cratered and is grey in color. There are three named craters on the surface of Puck, the largest being about 45 km in diameter. Observations with Hubble Space Telescope and large terrestrial telescopes found water ice absorption features in the spectrum of Puck.

Nothing is known about the internal structure of Puck. It is probably made of a mixture of water ice with the dark material similar to that found in the rings. This dark material is probably made of rocks or radiation-processed organics. The absence of craters with bright rays implies that Puck is not differentiated, meaning that ice and non-ice components have not separated from each other forming a core and mantle.