Nereid (moon)

Nereid
Nereid imaged by Voyager 2 in 1989
Discovery[1]
Discovered byGerard P. Kuiper
Discovery date1 May 1949
Designations
Designation
Neptune II
Pronunciation/ˈnɪəriəd/ NEER-ee-əd[2]
Named after
Νηρηΐδες Nērēḯdes
AdjectivesNereidian or Nereidean (both /ˌnɛriˈɪdiən/ NERR-ee-ID-ee-ən)[3]
Orbital characteristics[4]
Epoch 1 January 2020 (JD 2458849.5)
Observation arc27,603 d (75.57 yr)
5,504,000 km (0.03679 AU)
Eccentricity0.749
360.14 d (0.9860 yr)
318.0°
0° 59m 58.597s / day
Inclination5.8° (to the ecliptic)
7.090° (to local Laplace plane)[4]
326.0°
290.3°
Satellite ofNeptune
Physical characteristics
357±13 km[5]
Flattening≤0.23[a]
Mass3.57×1019 kg
(5.98×10−6 M🜨)
Mean density
1.5 g/cm3 (assumed)[6]
≈0.075 m/s2 (0.0076 g)
11.594±0.017 h[5]
Albedo0.24[5]
Temperature≈50 K (mean estimate)
19.2[citation needed]
4.4[7]

Nereid, or Neptune II, is the third-largest moon of Neptune. It has the most eccentric orbit of all known moons in the Solar System.[4] It was the second moon of Neptune to be discovered, by Gerard Kuiper in 1949.

  1. ^ Cite error: The named reference Kuiper 1949 was invoked but never defined (see the help page).
  2. ^ "Nereid". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. ^ "nereidian, nereidean". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  4. ^ a b c Cite error: The named reference JPL-SSD-Neptune was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Kiss2019 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference JPL-SSD-sat_phys was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference MPC115892 was invoked but never defined (see the help page).


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