A satellite of Jupiter, twelfth from the planet; also known as Jupiter X. Its distance is 11 717 000 km, close to that of Elara, and its orbital period is 259.2 days. Its diameter is 36 km. Lysithea was discovered in 1938 by the American astronomer Seth Barnes Nicholson (1891–1963). It is a member of the Himalia group of Jovian satellites.