Discovery of Themisto

Themisto is a small moon of Jupiter, about eight kilometers across, and the innermost of the irregular outer moons. It was first found on 30 September 1975 by Charles Kowal and Elizabeth Roemer, who observed it on photographic plates, but it was lost because there was not enough data to determine its orbit. It was recovered in 2000 by a team led by Scott Sheppard and David Jewitt, who were conducting a survey, and the two sightings were then recognized as the same object. Its orbit is unusual, as it does not belong to the larger groups of irregular moons. It is named for Themisto, a figure of Greek mythology.

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