Quaoar is a large, ringed trans-Neptunian object in the Kuiper belt, a region of icy planetesimals beyond Neptune. It has an elongated ellipsoid shape with an average diameter of 1,090 km (680 mi), about half the size of the dwarf planet Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at the Palomar Observatory on 4 June 2002. Quaoar's surface contains crystalline water ice and ammonia hydrate, which suggests that it might have experienced cryovolcanism. A small amount of methane is present on its surface, which can only be retained by the largest Kuiper belt objects.
Low-resolution Hubble Space Telescope image of Quaoar and its moon Weywot, February 2006
Quaoar was discovered using the Samuel Oschin telescope at Palomar Observatory
Artist's impression of Quaoar with its ring and its moon Weywot
A ring system is a disc or ring, orbiting an astronomical object, that is composed of solid material such as dust and moonlets, and is a common component of satellite systems around giant planets like Saturn. A ring system around a planet is also known as a planetary ring system.
The ring orbiting Saturn consists mostly of chunks of ice and dust. The small dark spot on Saturn is the shadow from Saturn's moon Enceladus.
A Galileo image of Jupiter's main ring.
A Cassini mosaic of Saturn's rings.
A pair of Voyager 2 images of Neptune's rings.