S/2021 N 1
< S
| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard David J. Tholen Chad Trujillo Patryk S. Lykawka |
| Discovery site | Mauna Kea Obs. |
| Discovery date | 7 September 2021 |
| Orbital characteristics | |
| Epoch 1 January 2020 (JD 2458849.5) | |
| Observation arc | 2.16 yr (788 d) |
| Satellite of | Neptune |
| Group | Neso group |
| Proper orbital elements | |
Proper semi-major axis | 50,700,200 km (0.338910 AU) AU |
Proper eccentricity | 0.503 |
Proper inclination | 50.2° (to ecliptic) |
Proper mean motion | 13.1009833 deg / yr |
Proper orbital period | 27.47885 yr (10036.651 d) |
Precession of the ascending node | 1402.42893 arcsec / yr |
| Physical characteristics | |
| 16–25 km 14 km | |
| 27 (average) | |
| 12.1 | |
S/2021 N 1 is the smallest, faintest, and most distant natural satellite of Neptune known, with a diameter of around 16–25 km (10–16 mi). It was discovered on 7 September 2021 by Scott S. Sheppard, David J. Tholen, Chad Trujillo, and Patryk S. Lykawka using the 8.2-meter Subaru Telescope at Mauna Kea, Hawaii, and later announced on 23 February 2024. It orbits Neptune in the retrograde direction at an average distance of over 50 million km (31 million mi) and takes about 27 Earth years to complete its orbit—the largest orbital distance and period of any known moon in the Solar System.