Praxidike (moon)

Praxidike, also known as , is a small [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 led by Scott S. Sheppard in 2000, and given the temporary designation .
It was named in August 2003 after Praxidike, the Greek goddess of punishment.

Orbit

Praxidike orbits Jupiter at an average distance of 21,147,000 km in 609.25 days, at an inclination of 149° to the ecliptic, in a retrograde direction and with an eccentricity of 0.230. 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

With a diameter of 7 km, Praxidike is the second largest member of the group after Ananke itself. Based on infrared heat measurements taken by the WISE space telescope, Praxidike's albedo was measured at 2.9%, making it one of the least reflective bodies in our solar system.
The satellite appears grey, typical of C-type asteroids.

Origin

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