None have ever been imaged by spacecraft, but there is evidence that Saturn's moon Phoebe may be a captured object of this type.
Due to their icy composition, some of these objects such as 60588 Echeclus can be classified as both asteroids and comets due to their exhibition of coma. Although they possess a wide variety of colors making the classification of surface composition difficult, they are usually classified into two major color groups: very red and blue-grey.  None have ever been imaged by spacecraft, but there is evidence that Saturn's moon Phoebe may be a captured object of this type. Orbiting between Jupiter and Neptune, FTP, what icy planetoids, the best known of which is Chiron, and are named after half- men, half-horses from Greek mythology.
Due to their icy composition, some of these objects such as 60588 Echeclus can be classified as both asteroids and comets due to their exhibition of coma.
{Centaurs}