Ananke group
The Ananke Group is a group of moons on the planet Jupiter that move in similar orbits.
The semi-major axes of their orbits thus extend km 19.3 to 22.7 million have eccentricities 0.02 to 0.28 and inclinations ( orbital inclinations ) between 145.7 ° and 154.8 ° to the local Laplace plane on , which at this distance from the planet roughly coincides with the plane of the orbit of Jupiter. The moons move retrograde around the planet, that is, against the direction of rotation of Jupiter. Since the maximum planetary distances of the group members make up up to 50% of the Hill radius , retrograde orbits at this distance from Jupiter are much more stable in the long term.
The number of members is between eight and sixteen, depending on how precisely the definition of the group is established.
The eight moons, which are assigned to the group in each case, are (arranged according to increasing distance from Jupiter):
- S / 2003 J 16
- Mnemes
- Euanthe
- Harpalyke
- Practice
- Thyone
- Ananke (the largest moon and namesake)
- Iocaste
The eight other moons are:
The International Astronomical Union (IAU) gives names to the retrograde moons of Jupiter with the ending e .