Ananke (moon)

Short description: Moon of Jupiter

Ananke

Ananke photographed by the Haute-Provence Observatory in August 1998

Discovery [1]
Discovered by| Seth B. Nicholson
Discovery site| Mt. Wilson Observatory
Discovery date| 28 September 1951
Designations

Designation

| Jupiter XII
Pronunciation| /əˈnæŋkiː/[2]
Named after| Ἀνάγκη Anagkē
Adjectives| Anankean /ænəŋˈkiːən/[3]
Orbital characteristics [4]
Epoch 17 December 2020 (JD 2459200.5)
Observation arc| 69.05 yr (24,338 days)

Semi-major axis

| 0.1406602 astronomical unit|AU (21,042,470 km)
Eccentricity| 0.1747248
Orbital period| –623.59 d
Mean anomaly| 339.61045°
Mean motion| 0° 34m 38.281s / day
Inclination| 148.67482° (to ecliptic)
Longitude of ascending node| 86.44368°

|{{{apsis}}}|helion}}

| 135.63033°
Satellite of| Jupiter
Group| Ananke group
Physical characteristics
Mean diameter| 29.1±0.6 km[5]
Rotation period| 8.31±0.15 h[6]
Albedo| 0.038±0.006[5]
Apparent magnitude| 18.9[7]
Absolute magnitude (H)| 11.7[4]

Ananke (/əˈnæŋki/) is a retrograde irregular moon of Jupiter. It was discovered by Seth Barnes Nicholson at Mount Wilson Observatory in 1951[1] and is named after the Greek mythological Ananke, the personification of necessity, and the mother of the Moirai (Fates) by Zeus. The adjectival form of the name is Anankean.

Ananke did not receive its present name[8] until 1975;[9] before then, it was simply known as Jupiter XII. It was sometimes called "Adrastea"[10] between 1955 and 1975 (Adrastea is now the name of another satellite of Jupiter).

Ananke gives its name to the Ananke group, retrograde irregular moons which orbit Jupiter between 19.3 and 22.7 Gm, at inclinations of roughly 150°.[11]

## Contents

* 1 Orbit
* 2 Physical characteristics
* 3 See also
* 4 References
* 5 External links

## Orbit

Retrograde irregular satellites of Jupiter.

Ananke orbits Jupiter on a high-eccentricity and high-inclination retrograde orbit. Fifteen irregular satellites orbiting Jupiter have been discovered since 2000 following similar orbits.[11] The orbital elements are as of January 2000.[12] They are continuously changing due to solar and planetary perturbations. The diagram illustrates Ananke's orbit in relation to other retrograde irregular satellites of Jupiter. The eccentricity of selected orbits is represented by the yellow segments (extending from the pericentre to the apocentre). The outermost regular satellite Callisto is located for reference.

Given these orbital elements and the physical characteristics known so far, Ananke is thought to be the largest remnant[13] of an original break-up, forming the Ananke group.[14][15]

## Physical characteristics

Single-exposure image of Ananke by the Wide-field Infrared Survey Explorer (WISE) spacecraft in 2010

In the visible spectrum, Ananke appears neutral to light-red (colour indices B-V=0.90 V-R=0.38).[15]

The infrared spectrum is similar to P-type asteroids but with a possible indication of water.[16]

## See also

* Irregular satellites

## References

1. ↑ 1.0 1.1 Nicholson, S. B. (1951). "An unidentified object near Jupiter, probably a new satellite". Publications of the Astronomical Society of the Pacific 63 (375): 297–299. doi:10.1086/126402. Bibcode: 1951PASP...63..297N. http://adsabs.harvard.edu//full/seri/PASP./0063//0000297.000.html.
2. ↑ "Ananke". Dictionary.com Unabridged. Random House. https://www.dictionary.com/browse/Ananke.
3. ↑ Yenne (1987) The Atlas of the Solar System.
4. ↑ 4.0 4.1 "M.P.C. 127087". Minor Planet Circular. Minor Planet Center. 17 November 2020. https://minorplanetcenter.net/iau/ECS/MPCArchive/2020/MPC_20201117.pdf.
5. ↑ 5.0 5.1 Grav, T.Expression error: Unrecognized word "etal". (August 2015). "NEOWISE: Observations of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal 809 (1): 9. doi:10.1088/0004-637X/809/1/3. 3. Bibcode: 2015ApJ...809....3G.
6. ↑ Luu, Jane (September 1991). "CCD photometry and spectroscopy of the outer Jovian satellites". Astronomical Journal 102: 1213–1225. doi:10.1086/115949. ISSN 0004-6256. Bibcode: 1991AJ....102.1213L.
7. ↑ Sheppard, Scott. "Scott S. Sheppard - Jupiter Moons". Department of Terrestrial Magnetism. Carnegie Institution for Science. https://sites.google.com/carnegiescience.edu/sheppard/moons/jupitermoons.
8. ↑ Nicholson, S.B. (April 1939). "The Satellites of Jupiter". Publications of the Astronomical Society of the Pacific 51 (300): 85–94. doi:10.1086/125010. Bibcode: 1939PASP...51...85N. http://adsabs.harvard.edu//full/seri/PASP./0051//0000093.000.html.
9. ↑ Marsden, B. G. (7 October 1974). "Satellites of Jupiter". IAU Circular 2846. http://www.cbat.eps.harvard.edu/iauc/02800/02846.html.
10. ↑ Payne-Gaposchkin, Cecilia; Katherine Haramundanis (1970). Introduction to Astronomy. Englewood Cliffs, N.J.: Prentice-Hall. ISBN 0-13-478107-4.
11. ↑ 11.0 11.1 Sheppard, S. S., Jewitt, D. C., Porco, C.; Jupiter's Outer Satellites and Trojans , in Jupiter: The Planet, Satellites and Magnetosphere, edited by Fran Bagenal, Timothy E. Dowling, William B. McKinnon, Cambridge Planetary Science, Vol. 1, Cambridge, UK: Cambridge University Press, ISBN 0-521-81808-7, 2004, pp. 263-280
12. ↑ Jacobson, R. A. (2000). "The Orbits of the Outer Jovian Satellites". Astronomical Journal 120 (5): 2679–2686. doi:10.1086/316817. Bibcode: 2000AJ....120.2679J. https://trs.jpl.nasa.gov/bitstream/2014/15175/1/00-1187.pdf.
13. ↑ Sheppard, S.S.; Jewitt, D.C. (2003). "An abundant population of small irregular satellites around Jupiter". Nature 423 (6937): 261–263. doi:10.1038/nature01584. PMID 12748634. Bibcode: 2003Natur.423..261S. http://www.ifa.hawaii.edu/~jewitt/papers/JSATS/SJ2003.pdf.
14. ↑ Nesvorný, D.; Beaugé, C.; Dones, L. (2004). "Collisional Origin of Families of Irregular Satellites". The Astronomical Journal 127 (3): 1768–1783. doi:10.1086/382099. Bibcode: 2004AJ....127.1768N. http://www.iop.org/EJ/article/1538-3881/127/3/1768/203442.html.
15. ↑ 15.0 15.1 Grav, Tommy; Holman, M. J.; Gladman, B. J.; Aksnes, K. (2003). "Photometric survey of the irregular satellites". Icarus 166 (1): 33–45. doi:10.1016/j.icarus.2003.07.005. Bibcode: 2003Icar..166...33G.
16. ↑ Grav, Tommy; Holman, Matthew J. (2004). "Near-Infrared Photometry of the Irregular Satellites of Jupiter and Saturn". The Astrophysical Journal 605 (2): L141–L144. doi:10.1086/420881. Bibcode: 2004ApJ...605L.141G.

Sources

* Ephemeris IAU-MPC NSES

## External links

* Ananke Profile by NASA's Solar System Exploration
* David Jewitt pages
* Scott Sheppard pages

* v
* t
* e

Moons of Jupiter

Listed in approximately increasing distance from Jupiter. Provisional designations in italics.

Inner moons|

* Metis
* Adrastea
* Amalthea
* Thebe

Galilean moons|

* Io
* Europa
* Ganymede
* Callisto

Themisto group|

* Themisto

Himalia group|

* Leda
* Himalia
* Ersa
* Pandia
* Lysithea
* Elara
* Dia

Carpo group|

* Carpo

Valetudo group|

* Valetudo

Ananke group|

* S/2003 J 12(?)
* Euporie
* Eupheme
* Jupiter LV
* Jupiter LII
* Thelxinoe
* Euanthe
* Helike
* Orthosie
* Jupiter LXVIII
* Jupiter LIV
* Jupiter LXIV
* Iocaste
* S/2003 J 16(?)
* Praxidike
* Harpalyke
* Mneme
* Hermippe
* Thyone
* Jupiter LXX
* Ananke

Carme group|

* Jupiter LXXII
* Herse
* Aitne
* Kale
* Taygete
* Jupiter LXI
* Chaldene
* S/2003 J 10(?)
* Erinome
* Kallichore
* Jupiter LXVI
* Jupiter LXIX
* Kalyke
* Carme
* Jupiter LXIII
* Pasithee
* Jupiter LI
* Eukelade
* Arche
* Isonoe
* S/2003 J 9(?)
* Eirene

Pasiphae group|

* Jupiter LXVII
* Philophrosyne
* S/2003 J 23(?)
* Aoede
* Callirrhoe
* Eurydome
* Kore
* Cyllene
* Jupiter LVI
* Jupiter LIX
* S/2003 J 4(?)
* Pasiphae
* Hegemone
* Sinope
* Sponde
* Autonoe
* Megaclite
* S/2003 J 2(?)

* Rings of Jupiter
* In fiction

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