Orcus (dwarf planet)
| 2004 DW | |
|---|---|
| Orbital characteristics | |
| Orbit type | Plutino |
| Semimajor axis | 39.488 AU |
| Eccentricity | 0.2177 |
| Orbital period | 248.0124 years |
| Inclination | 20.5553° |
| Perihelion distance | 30.8723 AU |
| Aphelion distance | 48.0755 AU |
| Distance from the sun in 2004 | ~45 AU |
| Physical characteristics | |
| Equatorial diameter | ~1,600 +280-760 km |
| Mass | ?×10? kg |
| Density | ? g/cm3 |
| Rotation period | ?h |
| Albedo | 0.09 |
| Absolute magnitude | 2.2 |
| History | |
| Discoverers | M. Brown, C. Trujillo, D. Rabinowitz |
| Discovery date | 2004-02-18 |
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 magnitude
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).
Name
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.
