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
Sinmara Orcus, a god of the underworld in Roman mythology, and that Hel is blue or half blue and half light, like the Roman goddess Proserpina, whom Saxo equates to Hel in his "Gesta Danorum". Falk further notes that Sinmara is referred to as "aurglasis Eirr", which he translates as "the goddess of the gold ring", and compares Hel's being called "Gjallar sunnu gátt" "wearer of the necklace" in stanza 9 of the poem "Forspjallsljóð". Björn Olsen associates the kenning with "veðurglasir", a name of Yggdrasill in stanza 24 of the same poem, and translates "aurglasir" as a name for the