1998 WW31
Encyclopedia
is a double
Kuiper belt
object. It was discovered in 1998 by the Deep Ecliptic Survey
(DES).
forms a binary system
with another object with the IAU
provisional designation : 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.
Double planet
In astronomy, double planet and binary planet are informal terms used to describe a binary system of two astronomical objects that each satisfy the definition of planet and that are near enough to each other to have a significant gravitational effect on each other compared with the effect of the...
Kuiper belt
Kuiper belt
The Kuiper belt , sometimes called the Edgeworth–Kuiper belt, is a region of the Solar System beyond the planets extending from the orbit of Neptune to approximately 50 AU from the Sun. It is similar to the asteroid belt, although it is far larger—20 times as wide and 20 to 200 times as massive...
object. It was discovered in 1998 by the Deep Ecliptic Survey
Deep Ecliptic Survey
The Deep Ecliptic Survey is a project to find Kuiper belt objects , using the facilities of the National Optical Astronomy Observatory .The principal investigator is Bob Millis....
(DES).
forms a binary system
Binary system (astronomy)
A binary system is an astronomical term referring to two objects in space which are so close that their gravitational interaction causes them to orbit about a common center of mass. Some definitions A binary system is an astronomical term referring to two objects in space (usually stars, but also...
with another object with the IAU
IAU
IAU may refer to:*International Astronomical Union*International American University*International American University College of Medicine*International Association of Universities*International Association of Ultrarunners...
provisional designation : the first trans-Neptunian
Trans-Neptunian object
A trans-Neptunian object is any minor planet in the Solar System that orbits the Sun at a greater distance on average than Neptune.The first trans-Neptunian object to be discovered was Pluto in 1930...
binary to be discovered since Pluto
Pluto
Pluto, formal designation 134340 Pluto, is the second-most-massive known dwarf planet in the Solar System and the tenth-most-massive body observed directly orbiting the Sun...
, 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
Semi-major axis
The major axis of an ellipse is its longest diameter, a line that runs through the centre and both foci, its ends being at the widest points of the shape...
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.