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1998 WW31
From Wikipedia, the free encyclopedia
- The correct title of this article is 1998 WW31. It features superscript or subscript characters that are substituted or omitted because of technical limitations.
| Discovery | |
|---|---|
| Discovered by: | Deep Ecliptic Survey |
| Discovery date: | 18 November 1998 |
| MPC designation: | 1998 WW31 |
| Alternative names: | none |
| Minor planet category: | Trans-Neptunian object |
| Orbital characteristics | |
| Epoch June 14, 2006 (JD 2453900.5) | |
| Aphelion distance: | 7243.350 Gm (48.419 AU) |
| Perihelion distance: | 6067.553 Gm (40.559 AU) |
| Semi-major axis: | 6655.451 Gm (44.489 AU) |
| Eccentricity: | 0.088 |
| Orbital period: | 108386.849 d (296.75 a) |
| Avg. orbital speed: | 4.46 km/s |
| Mean anomaly: | 126.983° |
| Inclination: | 6.818° |
| Longitude of ascending node: | 237.108° |
| Argument of perihelion: | 49.588° |
| Satellites: | 1 |
| Physical characteristics | |
| Dimensions: | 133±15 km |
| Mass: | 1.3–2.5×1018 kg (system) |
| Mean density: | 1.5 g/cm³ (assumed) |
| Equatorial surface gravity: | 0.025–0.031 m/s² |
| Escape velocity: | 0.054–0.068 km/s |
| Sidereal rotation period: | 570 d (system orbital period) |
| Albedo: | 0.05-0.09 (assumed) |
| Temperature: | ~42 K |
| Spectral type: | ? |
| Absolute magnitude: | 6.05 |
1998 WW31 (also written 1998 WW31) is an object of the solar system located beyond the orbit of Neptune. It was discovered in 1998 by the Deep Ecliptic Survey (DES).
1998 WW31 forms a binary system with another object with the IAU provisional designation S/2000 (1998 WW31) 1; the first trans-Neptunian binary to be discovered since Pluto, and the most symmetrical binary known in the Solar system. The two bodies are very close in size, with a diameter ratio of 1.2 and a mass ratio of 1.74, assuming similar surfaces and densities. Their orbital period is approximately 570 days, and they orbit at a distance of approximately 4000 km (closest approach) to 40,000 km, with a semi-major axis of about 22,000 km. Their diameters are likely to be in the 100-150 km range, assuming a density of 1-2 g/cc. Their combined mass is 1/6000th that of the Pluto-Charon system.
- The IAU circular announcing the discovery of the companion
- 1998 WW31 and S/2000 (1998 WW31) 1
- Discussion at CFHT, Hawaii
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Vulcanoids · Near-Earth asteroids · Main belt · Jupiter Trojans · Centaurs · Damocloids · Comets · Trans-Neptunians (Kuiper belt • Scattered disc • Oort cloud)
For other objects and regions, see Asteroid groups and families, Binary asteroids, Asteroid moons and the Solar System.
For a complete listing, see List of asteroids. See also Pronunciation of asteroid names and Meanings of asteroid names.