Elara

astronomy

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June 17, 2026

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Elara is a moon of Jupiter, discovered in 1905 by Charles Dillon Perrine. It is the seventh moon of Jupiter in order of distance from the planet and is part of Jupiter's outer irregular satellite group. Elara orbits Jupiter at a mean distance of 11,741,000 km with an orbital period of 259.6 Earth days.12

Like many of Jupiter's outer moons, Elara has a retrograde orbit, meaning it travels in the opposite direction of Jupiter's rotation. Its orbit is also inclined, deviating significantly from Jupiter's equatorial plane. Elara is a relatively small celestial body, with a radius of approximately 43 km. Its low density suggests a porous structure, possibly resulting from past collisions.21

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Jupiter
Other satellites
Himalia, Lysithea, and Elara—has prograde orbits. (In the case of these moons, retrograde motion is in the direction opposite to Jupiter’s spin and motion around the Sun, which are counterclockwise as viewed from above Jupiter’s north pole, whereas prograde, or direct, motion is in the same direction.) In…
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Himalia, Lysithea, and Elara—has prograde orbits. (In the case of these moons, retrograde motion is in the direction opposite to Jupiter’s spin and motion around the Sun, which are counterclockwise as viewed from above Jupiter’s north pole, whereas prograde, or direct, motion is in the same direction.) In…
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