S/2021 J 2 Explained

S/2021 J 2
Discoverer:Scott S. Sheppard
Discovery Site:Las Campanas Obs.
Discovered:12 August 2021
Epoch:25 February 2023 (JD 2460000.5)
Observation Arc:1.06 yr (387 d)
Eccentricity:0.3413342
Period:–1.72 yr (–627.96 days)
Mean Anomaly:320.08120°
Mean Motion: / day
Inclination:150.11397°
Asc Node:340.99094°
Arg Peri:71.71210°
Satellite Of:Jupiter
Group:Ananke group
Mean Diameter:
Magnitude:24.0
Abs Magnitude:17.3

S/2021 J 2 is a small outer natural satellite of Jupiter discovered by Scott S. Sheppard on 12 August 2021, using the 6.5-meter Magellan-Baade Telescope at Las Campanas Observatory, Chile. It was announced by the Minor Planet Center on 19 January 2023, after observations were collected over a long enough time span to confirm the satellite's orbit.

S/2021 J 2 is part of the Ananke group, a cluster of retrograde irregular moons of Jupiter that follow similar orbits to Ananke at semi-major axes between NaNe6km, orbital eccentricities between 0.1–0.4, and inclinations between 139–155°. It has a diameter of about for an absolute magnitude of 17.3, making it one of Jupiter's smallest known moons.