90482 Orcus given the designation S/2005 (90482) 1 before later being named "Vanth". It orbits Orcus in a nearly face-on circular orbit with an eccentricity of about 0.007, and an orbital period of 9.54 days. Vanth orbits only from Orcus and is too close to Orcus for ground-based spectroscopy to determine the surface composition of the satellite. Mike Brown suspects that like the Pluto–Charon system, Orcus and Vanth are tidally locked. Vanth does not resemble known collisional satellites because its spectrum is very different from that of its primary, and it may be a captured KBO. Vanth could also have originated as
Orcus Orcus Orcus () was a god of the underworld, punisher of broken oaths in Italic and Roman mythology. As with Hades, the name of the god was also used for the underworld itself. In the later tradition, he was conflated with Dis Pater. Orcus was portrayed in paintings in Etruscan tombs as a hairy, bearded giant. A temple to Orcus may have existed on the Palatine Hill in Rome. It is likely that he was transliterated from the Greek daemon Horkos, the personification of Oaths and a son of Eris. The origins of Orcus may have lain in Etruscan religion.