Which Jupiter moon is its largest irregular satellite?

Jupiter's largest irregular satellite is Himalia. Unlike the four large Galilean moons, Himalia follows a distant, inclined, and noticeably eccentric orbit, characteristics that place it among Jupiter's irregular satellites.

Himalia was discovered by Charles Dillon Perrine at California's Lick Observatory on December 3, 1904. It is roughly 140 kilometers across, making it only the sixth-largest Jovian moon overall: Ganymede, Callisto, Io, Europa, and Amalthea are larger. It is nevertheless the biggest member of the Himalia group, a family of prograde irregular moons with similar orbital properties.

Scientists think Himalia was probably captured by Jupiter rather than formed in its present location. The Himalia group may be the debris of a once-larger asteroid broken apart by a collision. That origin helps explain why these moons orbit far beyond Jupiter's regular satellite system.

The main trap is the word “largest.” Amalthea is a larger regular moon, while Ganymede is Jupiter's largest moon overall. Himalia is specifically the largest irregular satellite. Its name comes from Himalia, a nymph in Greek mythology associated with Zeus, Jupiter's Greek counterpart.