Ananke (moon)

Template:Short description Template:Use dmy dates {{#invoke:infobox|infoboxTemplate | class = vcard | titleclass = fn org | title = Ananke | image = {{#invoke:InfoboxImage|InfoboxImage|image=Ananké.jpg|upright={{#if:||1.1}}|alt=}} | caption = Ananke photographed by the Haute-Provence Observatory in August 1998 | headerstyle = {{#if:|background-color:|background-color:#E0CCFF}} | labelstyle = max-width:{{#if:||11em}}; | autoheaders = y

| header1 = Discovery<ref name="Nicolson1951"/>

| label2 = Discovered by | data2 = Seth B. Nicholson | label3 = Discovery site | data3 = Mt. Wilson Observatory | label4 = Discovery date | data4 = 28 September 1951 | label5 = Template:Longitem | data5 =

| header10 = {{#if:|Designations|Designations}}

| label11 = Template:Longitem | data11 = Jupiter XII | label12 = Pronunciation | data12 = Template:IPAc-en<ref>Template:Dict.com</ref> | label13 = Template:Longitem | data13 = Ἀνάγκη Anagkē | label14 = Template:Longitem | data14 = | label15 = Template:Longitem | data15 = | label16 = Adjectives | data16 = Anankean Template:IPAc-en<ref>Yenne (1987) The Atlas of the Solar System.</ref> | label17 = Symbol | data17 =

| header20 = Orbital characteristics{{#ifeq:|yes| (barycentric)}}<ref name="MPC127087"/>

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| header60 = Proper orbital elements

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| header70 = Template:Anchor{{#if:| Physical characteristics|Physical characteristics}}

| label71 = Dimensions | data71 = | label72 = Template:Longitem | data72 = Template:Val<ref name="Grav2015"/> | label73 = Template:Longitem | data73 = | label74 = Template:Longitem | data74 = | label75 = Template:Longitem | data75 = | label76 = Flattening | data76 = | label77 = Circumference | data77 = | label78 = Template:Longitem | data78 = | label79 = Volume | data79 = | label80 = Mass | data80 = Template:Val (calculated) | label81 = Template:Longitem | data81 = 1.30 g/cm³ (assumed)<ref>Template:Cite journal</ref> | label82 = Template:Longitem | data82 = | label83 = Template:Longitem | data83 = | label84 = Template:Longitem | data84 = | label85 = Template:Longitem | data85 = Template:Val<ref name="Luu1991"/> | label86 = Template:Longitem | data86 = | label87 = Template:Longitem | data87 = | label88 = Template:Longitem | data88 = | label89 = Template:Longitem | data89 = | label90 = Template:Longitem | data90 = | label91 = Template:Longitem | data91 = | label92 = Template:Longitem | data92 = | label93 = {{#if: |Template:Longitem |Albedo}} | data93 = Template:Val<ref name="Grav2015"/> | label94 = Temperature | data94 =

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| label101 = Surface absorbed dose rate | data101 = | label102 = Surface equivalent dose rate | data102 = | label103 = Template:Longitem | data103 = | label104 = Template:Longitem | data104 = | label105 = Template:Longitem | data105 = 18.9<ref name="SheppardMoons"/> | label106 = Template:Longitem | data106 = 11.7<ref name="MPC127087"/> | label107 = Template:Longitem | data107 =

| header110 = Atmosphere

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Ananke (Template:IPAc-en) is a retrograde irregular moon of Jupiter. It was discovered by Seth Barnes Nicholson at Mount Wilson Observatory in 1951.<ref name="Nicolson1951">Template:Cite journal</ref> It 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<ref name="Nicholson1938">Template:Cite journal</ref> until 1975;<ref name="IAUC 2846">Template:Cite journal</ref> before then, it was simply known as Template:Nowrap. It was sometimes called "Adrastea"<ref name="Gaposchkin">Template:Cite book</ref> 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°.<ref name="SheppardJewittPorco2004">Sheppard, S. S., Jewitt, D. C., Porco, C.; Jupiter's Outer Satellites and Trojans Template:Webarchive, 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, Template:ISBN, 2004, pp. 263-280</ref>

Orbit

File:TheIrregulars JUPITER retro.svg

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.<ref name="SheppardJewittPorco2004"/> The orbital elements are as of January 2000.<ref name="Jacobson 2000">Template:Cite journal</ref> 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<ref name="SheppardJewitt2003">Template:Cite journal</ref> of an original break-up, forming the Ananke group.<ref name="Nesvorny2004"> Template:Cite journal</ref><ref name="Grav2003">Template:Cite journal</ref>

Physical characteristics

File:Ananke WISE-W3.jpg

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).<ref name="Grav2003"/>

The infrared spectrum is similar to P-type asteroids but with a possible indication of water.<ref name="Grav2004">Template:Cite journal</ref>

See also

• Irregular satellites

External links

• IAU-MPC NSES
• Ananke Profile by NASA's Solar System Exploration
• David Jewitt pages
• Scott Sheppard pages