[053] Dia

Dia /ˈdaɪ.ə/, also known as Jupiter LIII, is a prograde irregular satellite of Jupiter. Provisionally known as S/2000 J 11, it received its name on March 7, 2015.^[4] It is named after Dia, daughter of Deioneus (or Eioneus), wife of Ixion. According to Homer, she was seduced by Zeus in stallion form; Pirithous was the issue.

The satellite is one of several known small bodies in the Himalia group.^[5]

Dia is thought to be about 4 kilometres in diameter.^[6] It orbits Jupiter at an average distance of 12 million km in 274 days, at an inclination of 28° (to Jupiter's equator), and with an eccentricity of 0.21.^[7]

Observational history

Dia was discovered by a team of astronomers from the University of Hawaiʻi led by Scott S. Sheppard in 2000 with an observation arc of 26 days.^[8][9]

Initial observations were not followed up, and Dia was not observed for more than a decade after 2000. This apparent disappearance led some astronomers to consider the moon lost.^[10] One theory was that it had crashed into Himalia, creating a faint ring around Jupiter.^[11] However, it was finally recovered in observations made in 2010 and 2011.^[7]