Ananke
Ananke is one of the largest of the outer irregular satellites of Jupiter. Before 1975 it was known simply as Jupiter XI. It gives its name to the Ananke group of retrograde irregular satellites that follow similar orbits to Ananke and are thought to have a common origin. Their semi-major axes (distances from Jupiter) range between 19.3 and 22.7 million kilometers, their orbital inclinations between 145.7° and 154.8°, and their orbital eccentricities between 0.02 and 0.28.
discovery | 1951, by Seth Barnes Nicholson |
semimajor axis | 21,455,000 km (13,334,000 mi) |
diameter | 28 km (17 mi) |
mean density | 2.6 g/cm3 |
escape velocity | 0.017 km/s (61 km/h, 38 mph) |
orbital period | -642.02 days (retrograde) |
orbital eccentricity | 0.345 |
orbital inclination | 151.56° |