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
Tomb of Orcus "during the magistracy of Velu Hulchnie", found elsewhere in the tomb). According to this interpretation, the phrase would translate: Le[ive] erected this monument for posterity [during the magistracy] of Larth Hulchnie and Marce Caliathe. "Marce" is probably a cognate or preform of "Marcus". "Hulchnie" is generally interpreted as the Roman gens "Fulcinius", and "Larth" is believed to be akin to the Greek name "Laertēs"; some have suggested that "Larth Hulchnie" means "Hulchnie, son of Larth". Tomb of Orcus The Tomb of Orcus (), sometimes called the Tomb of Murina (), is a 4th-century BC Etruscan hypogeum (burial chamber) in Tarquinia,