Name

Diameter
Orbit
million km

Period
Ananke 28 km 21.3 610.5 days In fact, its highly eccentric orbit varies between 12.6 and 29.1 million km. 
Praxidike 7 km 20.8 625.4 days I am not sure of the significance, but the moon is named for Praxidike,
the Greek goddess of punishment.
Iocaste 5 km 20.7 609.4 days
Harpalyke 4 km 21.1 624.5 days
Thyone 4 km 21.4 639.8 days
Euanthe 3 km 20.5 598.1 days
Euporie 2 km 19.1 538.8 days
Helike 4 km 20.5 601.4 days
Hermippe 4 km 21.2 629.8 days
Mneme 2 km 21.4 640.8 days
Orthosie 2 km 20.6 622.6 days
Thelxinoe 2 km 20.5 628.1 days Period was quoted as 597.6 days; new figure is from NASA.
WILLIAM & DEBORAH HILLYARD

Solar System -

Jupiter's Moons

Ananke Group

The Ananke Group of retrograde, irregular moons comprises at least fifteen known moons, though not all have been named.  All these moons orbit Jupiter at average distances between 19.3 and 22.7 million km (14.2 and 15 million miles).  The orbits are highly eccentric, and continuously changing due to perturbation from the Sun and the other planets.  It is likely that the Ananke group formed when a captured asteroid broke up as a result of a low velocity collision. The orbits and inclinations of the various moons are very similar.  Where color measurements have been obtained, they are, again, very similar.  It is likely that Ananke was the parent, and the other moons broke off. 
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