S/2021 J 1

S/2021 J 1 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 5 January 2023, after observations were collected over a long enough time span to confirm the satellite's orbit.^[1]

S/2021 J 1

Discovery[1]
Discovered by	Scott S. Sheppard
Discovery site	Las Campanas Obs.
Discovery date	12 August 2021
Orbital characteristics[1][2]
Epoch 25 February 2023 (JD 2460000.5)
Observation arc	1.06 yr (387 d)
Semi-major axis	0.1381519 AU (20,667,230 km)
Eccentricity	0.2460574
Orbital period (sidereal)	–1.66 yr (–606.99 days)
Mean anomaly	312.94753°
Mean motion	0° 35m 35.137s / day
Inclination	149.75284° (to ecliptic)
Longitude of ascending node	310.98434°
Argument of perihelion	73.05108°
Satellite of	Jupiter
Group	Ananke group
Physical characteristics
Mean diameter	≈1 km[3]
Apparent magnitude	23.9[3]
Absolute magnitude (H)	17.3[1]

S/2021 J 1 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 19–22 million km (12–14 million mi), orbital eccentricities between 0.1–0.4, and inclinations between 139–155°.^[3] It has a diameter of about 1 km (0.62 mi) for an absolute magnitude of 17.3, making it one of Jupiter's smallest known moons.^[3]

References

1. "MPEC 2023-A14 : S/2021 J 1". Minor Planet Electronic Circulars. Minor Planet Center. 5 January 2023. Retrieved 10 January 2023.
2. "Planetary Satellite Discovery Circumstances". JPL Solar System Dynamics. NASA. Retrieved 10 January 2023.
3. Sheppard, Scott S. "Moons of Jupiter". Earth & Planets Laboratory. Carnegie Institution for Science. Retrieved 10 January 2023.