Dia, also known as Jupiter LLI, is a prograde irregular satellite of the planet Jupiter. The moon was previously known as S/2000 J 11 until it received its official name on March 7, 2015.
The moon's name comes from Greek mythology, and means "she who belongs to Zeus" (who became Jupiter in Roman mythology). Dia was the divine daughter of the seashore.
The satellite is one of the free small bodies in the Himalia group, the other two are S/2018 J 1 and S/2017 J 4.
Dia is speculated to be about 4 kilometers in diameter. Dia orbits Jupiter at an average distance of around 12.1 million kilometers in 274 days, at an inclination of 28.2° (to Jupiter's equator). It has an eccentricity of 0.21.
Observational history[]
Dia was observed by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000 with an observation arc of 26 days.
Initial observations were not followed up, and Dia was not observed for more than a decade after 2000. The apparent disappearance of the moon led some astronomers to consider it "lost". One theory about the disappearance was that Dia crashed into Himalia and created a faint ring around Jupiter. The moon was finally found again and observed in 2010 and 2011.