Mneme (moon)

Mneme is a small, irregular moon of Jupiter. It belongs to the Ananke group, a family of retrograde irregular moons that share similar orbital characteristics and are believed to have a common origin.

Discovery and Naming

Mneme was discovered on February 9, 2003, by a team of astronomers led by Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, and Lynne Allen. It was initially given the temporary designation S/2003 J 21. In 2005, it was officially named after Mneme, one of the three original Muses in Greek mythology, representing memory. The other two Muses in that original group are Aoide (song/voice) and Melete (meditation/practice).

Orbital Characteristics

Mneme orbits Jupiter at an average distance of approximately 21,427,000 kilometers in about 640 Earth days. Its orbit is retrograde, meaning it orbits Jupiter in the opposite direction of Jupiter's rotation. The orbit has a high eccentricity and inclination, making it significantly elliptical and tilted relative to Jupiter's equatorial plane. These characteristics are typical of the Ananke group moons.

Physical Characteristics

Mneme is a small moon, estimated to be only about 2 kilometers in diameter. Given its small size and distance from Earth, little is known about its composition or surface features. It is presumed to be primarily composed of rock and ice, similar to other irregular moons of Jupiter. Its surface is likely heavily cratered due to impacts.

Ananke Group

Mneme is a member of the Ananke group, which includes other retrograde irregular moons like Ananke (the largest member), Euanthe, Harpalyke, Praxidike, Thelxinoe, Helike, Iocaste, and Orthosie. These moons are thought to be fragments of a larger object that was captured by Jupiter's gravity and subsequently shattered by collisions. The similar orbital parameters of these moons suggest a common origin.