Lysithea (moon)

Lysithea is one of the bigger moons that orbit the giant planet Jupiter. It is also called Jupiter X. Moons like Lysithea help scientists understand how our solar system began and how planets grow by pulling smaller objects into their paths. Looking at these faraway moons gives us hints about the early days of our solar system.

Discovery and Naming

Lysithea was found by Seth Barnes Nicholson in 1938 at Mount Wilson Observatory.

The moon is named after the mythological Lysithea, who was the daughter of Oceanus and one of Zeus’s lovers. Lysithea got its current name in 1975. Before that, it was called Jupiter X and was sometimes known as "Demeter" from 1955 to 1975.

Orbit

Lysithea travels around Jupiter at an average distance of 11,700,710 km. It completes one orbit in 258.57 days and moves in a forward direction, tilted about 27° compared to the plane where Earth orbits the Sun. The path of its orbit changes because of the pull of the Sun and other planets.

Lysithea is part of a group of moons called the Himalia group. These moons orbit Jupiter between 11 and 13 million kilometers away, with tilts between 27 and 30°, and their paths are not perfect circles.

Physical characteristics

Lysithea is a moon of Jupiter that is about 42 kilometers wide. It reflects light very weakly, with an albedo of about 3.6%. It is the fifth largest irregular moon of Jupiter.

Like other moons in the Himalia group, Lysithea looks gray and has colors similar to some asteroids. It spins around once roughly every 12 hours and 45.6 minutes.

Origin

Lysithea probably did not form close to Jupiter. Instead, Jupiter's gravity pulled it in later. It is similar to other moons in the Himalia group, which travel similar paths around Jupiter. Scientists think Lysithea might be a piece of an asteroid that broke apart and was captured by Jupiter.