5145 Pholus

5145 Pholus ("FOE luss") is a Centaur in an eccentric orbit, with a perihelion near the orbit of Saturn and aphelion near the orbit of Neptune. It is believed to have originated as a Kuiper belt object.

It was discovered by David L. Rabinowitz, then of the University of Arizona's Spacewatch Project, and named by him after Pholus, the brother of the mythological Chiron, after which 2060 Chiron was named.

Pholus was the second Centaur type asteroid to be discovered and was quickly found to be the reddest object observed to date in the Solar System, for which it has been occasionally nicknamed "Big Red". The color has been speculated to be due to organic compounds on its surface. Unlike the first Centaur, 2060 Chiron, Pholus has shown no signs of cometary activity.

The diameter of Pholus is estimated to be 185±16 km [1].