S/2021 N 1

S/2021 N 1
Discovery[1][2]
Discovered byScott S. Sheppard
David J. Tholen
Chad Trujillo
Patryk S. Lykawka
Discovery siteMauna Kea Obs.
Discovery date7 September 2021
Orbital characteristics[3]
Epoch 1 January 2020 (JD 2458849.5)
Observation arc2.16 yr (788 d)
0.367 km/s
Satellite ofNeptune
GroupNeso group
Proper orbital elements
50,700,200 km (0.338910 AU) AU
0.503
50.2° (to ecliptic)
13.1009833 deg / yr
27.47885 yr
(10036.651 d)
Precession of the ascending node
1402.42893 arcsec / yr
Physical characteristics
16–25 km[a]
14 km[5][6]
27 (average)[5]
12.1[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.[1] 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.

  1. ^ a b c Cite error: The named reference MPEC-2024-D112 was invoked but never defined (see the help page).
  2. ^ Cite error: The named reference jplsats-disc was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference jplsats-elem was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference cneos-diameter was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference SheppardMoons was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Carnegie-20240223 was invoked but never defined (see the help page).


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