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
Gate deities of the underworld only to the souls capable of pronouncing the secret name of the god himself, as a sort of "password". The walls of many Pharaonic tombs in the Valley of the Kings are decorated with the texts of the Book of Gates, which describes the twelve gates or pylons of the underworld: in spite of being imagined as architectural barriers to all intents and purposes, the gates were individually named as goddesses. Chapter 144 of the Book of the Dead mentions seven gates, each with its own God, a Doorkeeper and a Herald: for example, the 7th gate is guarded by