Aster › Space program › Orcus
Orcus
Position on the route: 74/130 · level needed 340 · journey (Mk0 engine) 58.8 h
By the numbers
| Diameter | ≈ 910 km |
|---|---|
| Year | 245 years |
| Semi-major axis | 39.2 AU |
| Moon | Vanth, ≈ 440 km |
The story
Orcus, found by Brown, Trujillo and Rabinowitz in 2004, is a Kuiper-belt object and a close ‘twin’ of Pluto: in the same 2:3 resonance with Neptune, but in opposite phase. When Pluto is ahead of Neptune, Orcus is on the exact other side; hence ‘anti-Pluto’. It is named for the Roman god of the underworld.
Its moon Vanth is almost half its size, which makes the pair close to a Pluto–Charon-style binary. Crystalline water ice and ammonia hydrate on the surface suggest that the body may have been resurfaced in the recent past.
Missions
- Hubble and JWST observations
- No mission planned
Colony note
No colony; a frontier outpost for ice and ammonia.
What probes bring back
- About 910 km; like Pluto it is in a 2:3 resonance with Neptune but in opposite phase: ‘anti-Pluto’. Its moon Vanth (≈440 km) is almost half its size.
- Crystalline water ice and ammonia hydrate on the surface: it may have been resurfaced in the recent past.