|Discovered by||University of Hawaiʻi team led by Scott S. Sheppard and David C. Jewitt|
|Discovery date||March 4, 2003|
|981.55 d (2.687 Earth years)|
Average orbital speed
|2.19 km/s (calculated)|
|Inclination||154° (to the ecliptic)
152° (to Jupiter's equator)
S/2003 J 2 is a retrograde irregular satellite of Jupiter. The discovery, by a team of astronomers from the University of Hawaii led by Scott S. Sheppard and David C. Jewitt, was announced on March 4, 2003. As of 2017[update], it is Jupiter's outermost known moon.
S/2003 J 2 is about 2 km (1.2 mi) in diameter, and orbits Jupiter at an average distance of 29.54 gigametres (0.1975 AU) in 981.55 days, at an inclination of 154° to the ecliptic (152° to Jupiter's equator) and with an eccentricity of 0.4100.
The limits of Jupiter's gravitational influence are defined by its Hill sphere, whose radius is 52 gigametres (0.35 AU). Retrograde moons with axes up to 67% of the Hill radius are believed to be stable. Consequently, it is possible that even more distant moons of Jupiter may be discovered.
We likely have all of the lost moons in our new observations from 2017, but to link them back to the remaining lost 2003 objects requires more observations a year later to confirm the linkages, which will not happen until early 2018. ... There are likely a few more new moons as well in our 2017 observations, but we need to reobserve them in 2018 to determine which of the discoveries are new and which are lost 2003 moons.