Iocaste (moon)

Iocaste, also known as , is a little [Prograde and Prograde and retrograde motion|retrograde motion|retrograde] irregular satellite of Jupiter.

Discovery and Naming

It was discovered by a team of astronomers from the University of Hawaiʻi including: David C. Jewitt, Yanga R. Fernandez, and Eugene Magnier led by Scott S. Sheppard in 2000, and given the temporary designation .
It was named in October 2002 after Jocasta, the mother/wife of Oedipus in Greek mythology. The name ending in "e" was chosen in accordance with the International Astronomical Union's policy for designating outer moons with retrograde orbits.

Orbit

Iocaste orbits Jupiter at an average distance of 21.431.650 in 641 earth days, at an inclination of 149° to the ecliptic with an eccentricity of 0.329. Its orbit is continuously changing due to solar and planetary perturbations.
It belongs to the Ananke group, made up a tightly of irregular retrograde moons orbiting Jupiter at a distance ranging between 19–22 million km, inclinations between 144 and 156°, and eccentricities between 0.10 and 0.30.

Physical characteristics

The satellite is about 5 kilometres in diameter and appears grey, similar to C-type asteroids.

Origin

Iocaste probably did not form near Jupiter but was captured by Jupiter later.Like the other members of the Ananke group, which have similar orbits, Iocaste is probably the remnant of a broken, captured heliocentric asteroid.