1998 WW31

1998 WW₃₁ (also written 1998 WW31) is a double Kuiper belt object. 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 one of the most symmetrical binaries 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/cm³. Their combined mass is 1/6000th that of the Pluto–Charon system.

References

External links

• The IAU circular announcing the discovery of the companion
• 1998 WW₃₁ and S/2000 (1998 WW31) 1
• Discussion at CFHT, Hawaii
• 1998 WW31 at the JPL Small-Body Database
  
  • Discovery · Orbit diagram · Orbital elements · Physical parameters