90482 Orcus: Encyclopedia - 90482 Orcus

90482 Orcus

90482 Orcus (originally known by the provisional designation 2004 DW) is a Kuiper Belt object (KBO) that was discovered by Michael Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. The discovery images of this object were acquired on February 17, 2004. Precovery images as early as November 8, 1951 were later identified.

90482 Orcus - Size and magnitude

The apparent magnitude of the object is 18.5, which is the same brightness as 50000 Quaoar. The orbit indicates that the object is a Plutino. Therefore, the object is probably larger than Quaoar, since it is farther from the Sun. Using an assumed albedo of 0.09, Trujillo estimates its diameter to be approximately 1600 km, which makes Orcus the sixth-largest discovered KBO, after 2003 UB₃₁₃, Pluto, 2005 FY₉, 2003 EL₆₁ and 90377 Sedna.

90482 Orcus - Name

Since it shares a similar size and orbit to that of Pluto, it too must be named after a deity of the underworld. In accordance with International Astronomical Union astronomical naming conventions, the discoverers' suggested name of Orcus was approved and published November 22, 2004. Orcus is both another name for the Greek deity Hades and a separate god of the dead in Roman mythology.

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