Icy body, similar to an asteroid in size but to a comet in composition, that orbits the Sun mainly between the orbits of Jupiter and Neptune.
The first known Centaur object, Chiron , was found in 1977, but its affinity with comets was not recognized until more than a decade later. Subsequently, dozens of Centaur objects have been reported. They are thought to have originated in the Kuiper belt , a vast reservoir of comet nuclei beyond Neptune 's orbit.