Depuis, non seulement Orcus a reçu un nom de baptême et non une simple plaque minéralogique mais l'on s'est aperçu que c'était la mésoplanète qui ressemble le + à Pluton tant au point de vue taille que pour son orbite en résonance avec celle de Neptune.

2004 DW is the temporary name given to the Kuiper Belt object (KBO) that was discovered by Mike Brown of Caltech, Chad Trujillo of the Gemini Observatory, and David Rabinowitz of Yale University. The image of this object was first detected on February 17, 2004.

Size and magnitudeModifier

The apparent magnitude of the object is 18.5, which is the same brightness as Quaoar. A very preliminary 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 2004 DW potentially the second-largest KBO, after Pluto. (The recently discovered Sedna, lying beyond the Kuiper Belt, may be the second-largest TNO).


The object's temporary name is International Astronomical Union (IAU) code. When read backwards, it means 2004 DW is the 22nd (the "W", I is skipped) solar system object discovered in the fourth half-month ("D", I and Z are skipped) of 2004. Within a few days, as the estimated 252-year orbit of 2004 DW is confirmed by the IAU, it will be assigned a number. Then the discoverers have 10 years from that date to propose a name for the object.

IAU rules further state that since 2004 DW shares a similar size and orbit to that of Pluto, it too must be named after a deity of the underworld.

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