Quaoar and Orcus

One of the largest KBOs is Quaoar (2002 LM60), named by its discoverers after the mythical creation-force figure of the Tongva tribe of the Los Angeles basin. Quaoar orbits the Sun every 288 years about a billion miles beyond the orbit of Pluto (somewhere around 42 AU). Quaoar was photographed in 1980, but was not recognized as a KBO until 2002, by Astronomer Mike Brown and his colleagues at Caltech in Pasadena, California.

Quaoar is about 1250 km in diameter, roughly the size of Pluto's moon Charon. Nothing larger has been found in our solar system since Pluto was discovered in 1930 (and Pluto's moon Charon in 1978). It's huge. In fact, if you took the 50,000 numbered asteroids and put them together, it would be about the same volume as Quaoar.

An even larger KBO (2004 DW, now officially named Orcus) was found at a distance of about 45 AU from the Sun.

2005 FY9, codenamed "Easterbunny," is a very large Kuiper belt object discovered on March 31, 2005 by the team led by Mike Brown at Caltech. Its discovery was announced on July 29, 2005 on the same day as two other very large trans-Neptunian objects (TNOs), 2003 EL61 and 2003 UB313, now officially known as Eris.