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| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard, David C. Jewitt, Yanga R. Fernández, and Eugene A. Magnier |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 5 December 2000 11 September 2012 (rediscovery) |
| Designations | |
Designation | Jupiter LIII |
| Pronunciation | /ˈdaɪ.ə/[1] |
| Named after | Δῖα Dīa |
| S/2000 J 11 | |
| Adjectives | Dian /ˈdaɪ.ən/ |
| Orbital characteristics [2] | |
| 12118000 km | |
| Eccentricity | 0.211 |
| Orbital period | +287.0 days |
| Mean anomaly | 169.9° |
| Inclination | 28.23° |
| Longitude of ascending node | 290.9° |
| 178.0° | |
| Satellite of | Jupiter |
| Group | Himalia group |
| Physical characteristics | |
| Mean diameter | 4 km |
| Apparent magnitude | 22.4 |
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.[3] 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.[4]
Dia is thought to be about 4 kilometres in diameter.[5] 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.[6]

Dia was discovered by a team of astronomers from the University of Hawaii led by Scott S. Sheppard in 2000 with an observation arc of 26 days.[7][8]
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.[9] One theory was that it had crashed into Himalia, creating a faint ring around Jupiter.[10] However, it was finally recovered in observations made in 2010 and 2011.[6]