90482 Orcus Etruscan equivalent of the Roman Pluto, and later became an alternate name for Pluto. The surface of Orcus is relatively bright with albedo reaching 23%, grey in color and water-rich. The ice is predominantly in crystalline form, which may be related to past cryovolcanic activity. Other compounds like methane or ammonia may also be present. The existence of a satellite allowed astronomers to determine the mass of the system, which is approximately equal to that of the Saturnian moon Tethys. The ratio of masses of Orcus and Vanth is uncertain, possibly anywhere from 1:33 to 1:12. The diameter of Orcus
Charon's obol "On the Nature of the Gods", Cicero identifies the Roman god Dis Pater with the Greek Pluton, explaining that riches are hidden in and arise from the earth. Dis Pater is sometimes regarded as a chthonic Saturn, ruler of the , whose consort Ops was a goddess of abundance. The obscure goddess Angerona, whose iconography depicted silence and secrecy, and whose festival followed that of Ops, seems to have regulated communications between the realm of the living and the underworld; she may have been a guardian of both arcane knowledge and stored, secret wealth. When a Roman died, the treasury