Neso (moon)
![]() Neso imaged by theVery Large Telescope's FORS1 imager in September 2002 | |
Discovery[1][2] | |
---|---|
Discovered by |
|
Discovery site | Cerro Tololo Obs. |
Discovery date | 14 August 2002 |
Designations | |
Designation | Neptune XIII |
Pronunciation | /ˈniːsoʊ/ |
Named after | ΝησώNēsō |
S/2002 N 4 | |
Adjectives | Nesoan/nɪˈsoʊ.ən/orNesoian/nɪˈsoʊ.iən/ |
Orbital characteristics | |
Epoch1 January 2000(Proper orbital element) | |
Observation arc | 19.96yr(7,292 days)[3] |
11.2°(proper) | |
Satellite of | Neptune |
Group | Neso group |
Proper orbital elements[4] | |
Propersemi-major axis | 49,598,300 km = 0.332AU |
Propereccentricity | 0.455 |
Properinclination | 126.9° |
Propermean motion | 13.4246deg/yr |
Properorbital period | 26.81644yr (9794.705d) |
Precession of theascending node | 1161.3684arcsec/yr |
Physical characteristics | |
60 km(for albedo 0.04)[5] | |
Albedo | 0.04(assumed)[5] |
Spectral type | V–R=0.58±0.13[6] V–I =1.0±0.4[7] R–I =0.7±0.4[7] |
25.6±0.3(V-band)[7] | |
10.67[3] | |
Neso/ˈniːsoʊ/,also known asNeptune XIII,is the second-outermost knownnatural satelliteofNeptune,afterS/2021 N 1.It is aretrogradeirregular moondiscovered byMatthew J. Holman,Brett J. Gladman,et al.on 14 August 2002, though it went unnoticed until 2003.[2][8]Neso is the second-most distant moon of Neptune, with an average orbital distance of over 49 million km. At its farthest point of its orbit, the satellite is more than 72 million km from Neptune. This distance exceedsMercury'saphelion,which is approximately 70 million km from theSun.
![](https://upload.wikimedia.org/wikipedia/commons/thumb/d/da/TheIrregulars_NEPTUNE_GROUPS.svg/265px-TheIrregulars_NEPTUNE_GROUPS.svg.png)
Neso is also the moon with the second-longest orbital period, 26.67 years. It follows a retrograde, highlyinclined,and highlyeccentricorbit illustrated on the diagram in relation to other irregular satellites of Neptune. The satellites above the horizontal axis areprograde,the satellites beneath it are retrograde. The yellow segments extend from thepericentreto theapocentre,showing the eccentricity.
Neso is affected by theKozai mechanism.[9]
Neso is about 60 km (37 mi) in diameter based on an assumed albedo of 0.04.
Given the similarity of the orbit's parameters withPsamathe(S/2003 N 1), it was suggested that both irregular satellites could have a common origin in the break-up of a larger moon.[5]
Neso is named after one of theNereids.Before it was officially named on 3 February 2007 (IAUC 8802), Neso was known by its provisional designation,S/2002 N 4.
See also[edit]
References[edit]
- ^ JPL (21 July 2011)."Planetary Satellite Discovery Circumstances".Jet Propulsion Laboratory.Retrieved24 October2011.
- ^ab Green, Daniel W. E. (1 October 2003)."S/2001 U 2 and S/2002 N 4".IAU Circular.8213.Retrieved24 October2011.
- ^ab"Natural Satellites Ephemeris Service".Minor Planet Center.Retrieved14 June2023.Selection of Objects → "All Neptunian outer irregular satellites" → Check "I require Orbital Elements" → Get Information
- ^ Jacobson, R. A. (2008)."NEP078 – JPL satellite ephemeris".Planetary Satellite Mean Orbital Parameters.Retrieved23 September2009.
- ^abc Sheppard, Scott S.;Jewitt, David C.;Kleyna, Jan(2006). "A Survey for" Normal "Irregular Satellites around Neptune: Limits to Completeness".The Astronomical Journal.132(1): 171–176.arXiv:astro-ph/0604552.Bibcode:2006AJ....132..171S.doi:10.1086/504799.S2CID154011.
- ^Graykowski, Ariel; Jewitt, David (April 2018)."Colors and Shapes of the Irregular Planetary Satellites".The Astronomical Journal.155(4): 10.arXiv:1803.01907.Bibcode:2018AJ....155..184G.doi:10.3847/1538-3881/aab49b.184.
- ^abcMaris, Michele; Carraro, Giovanni; Melita, Mario; Parisi, Gabriela (March 2018)."Multicolor Photometry of the Neptune Irregular Satellite Neso".Research Notes of the American Astronomical Society.2(1).arXiv:1803.07957.Bibcode:2018RNAAS...2...42M.doi:10.3847/2515-5172/aab7fc.42.
- ^ Holman, M. J.;Kavelaars, J. J.;Grav, T.; et al. (2004)."Discovery of five irregular moons of Neptune"(PDF).Nature.430(7002): 865–867.Bibcode:2004Natur.430..865H.doi:10.1038/nature02832.PMID15318214.S2CID4412380.Retrieved24 October2011.
- ^Brozović, Marina; Jacobson, Robert A.; Sheppard, Scott S. (10 March 2011)."THE ORBITS OF NEPTUNE'S OUTER SATELLITES".The Astronomical Journal.141(4): 135.doi:10.1088/0004-6256/141/4/135.ISSN0004-6256.
- MPC: Natural Satellites Ephemeris Service
- Mean orbital parameters fromJPL