Prometheus (moon)

Template:Short description Template:For {{#invoke:infobox|infoboxTemplate | class = vcard | titleclass = fn org | title = Prometheus | image = {{#invoke:InfoboxImage|InfoboxImage|image=Prometheus 12-26-09b.jpg|upright={{#if:||1.1}}|alt=}} | caption = Prometheus image from Cassini (December 26, 2009) | headerstyle = {{#if:|background-color:|background-color:#E0CCFF}} | labelstyle = max-width:{{#if:||11em}}; | autoheaders = y

| header1 = Discovery

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

| header20 = Orbital characteristics{{#ifeq:|yes| (barycentric)}} Template:Sfn

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| header60 = Proper orbital elements

| label61 = Template:Longitem | data61 = {{#if: |{{{p_semimajor}}} AU}} | label62 = Template:Longitem | data62 = | label63 = Template:Longitem | data63 = | label64 = Template:Longitem | data64 = {{#if: |{{{p_mean_motion}}} deg Template:\yr}} | label65 = Template:Longitem | data65 = {{#if:|{{#expr:360/1 round 5}} yr
({{#expr:365.25*360/1 round 3}} d) }} | label66 = Template:Longitem | data66 = {{#if:|{{{perihelion_rate}}} arcsec Template:\yr }} | label67 = Template:Longitem | data67 = {{#if:|{{{node_rate}}} arcsec Template:\yr}}

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

| label71 = Dimensions | data71 = Template:Val km
(± Template:Val km)Template:Sfn Template:Rp | label72 = Template:Longitem | data72 = Template:Val Template:Sfn Template:Rp | 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 = Template:Val Template:Sfn Template:Rp | label80 = Mass | data80 = Template:Val Template:Efn | label81 = Template:Longitem | data81 = Template:Val Template:Sfn Template:Rp | label82 = Template:Longitem | data82 = Template:Val Template:Sfn Template:Rp | label83 = Template:Longitem | data83 = | label84 = Template:Longitem | data84 = Template:V2 km/s at longest axis
to Template:V2 km/s at poles | label85 = Template:Longitem | data85 = synchronous | label86 = Template:Longitem | data86 = | label87 = Template:Longitem | data87 = | label88 = Template:Longitem | data88 = zero | label89 = Template:Longitem | data89 = | label90 = Template:Longitem | data90 = | label91 = Template:Longitem | data91 = | label92 = Template:Longitem | data92 = | label93 = {{#if: |Template:Longitem |Albedo}} | data93 = 0.6 | label94 = Temperature | data94 = ≈ 74 K

| data100 = {{#if:|

Surface temp.	min	mean	max
{{{temp_name1}}}
{{{temp_name2}}}
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| header110 = Atmosphere

| below = {{#if:||Template:Reflist }}

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Prometheus Template:IPAc-en is an inner satellite of Saturn. It was discovered on 24 October 1980 from images taken by the Voyager 1 probe, and was provisionally designated Template:Nowrap.Template:Sfn

In late 1985 it was officially named after Prometheus, a Titan in Greek mythology.Template:Sfn It is also designated Template:Nowrap.Template:Sfn

Prometheus is extremely elongated, measuring approximately Template:Convert. It has several ridges and valleys and a number of impact craters of about Template:Convert diameter are visible, but it is less cratered than nearby Pandora, Epimetheus, and Janus. From its very low density and relatively high albedo, it is likely that Prometheus is a very porous icy body. There is much uncertainty in these values, however, and so this remains to be confirmed.

Interactions with F Ring and other moonsEdit

Prometheus is a shepherd satellite for the inner edge of Saturn's narrow F Ring. Pandora orbits just outside the F Ring, and has traditionally been viewed as an outer shepherd of the ring; however, recent studies indicate that only Prometheus contributes to the confinement of the ring.<ref name = "LakdawallaE2014">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref name="Cuzzi2014">Template:Cite journal</ref>

Images from the Cassini probe show that Prometheus's gravitational influence creates kinks and knots in the F Ring as it shepherds material from it. The orbit of Prometheus appears to be chaotic, due to a series of four 121:118 mean-motion resonances with Pandora.Template:Sfn The most appreciable changes in their orbits occur approximately every 6.2 years,Template:Sfn when the periapsis of Pandora lines up with the apoapsis of Prometheus, as they approach to within approximately 1400 km. Prometheus is itself a significant perturber of Atlas, with which it is in a 53:54 mean-longitude resonance.Template:Sfn

Selected imagesEdit

AnimationsEdit

NotesEdit

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ReferencesEdit

CitationsEdit

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SourcesEdit

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External linksEdit

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Prometheus Profile at NASA's Solar System Exploration site
The Planetary Society: Prometheus
3-D anaglyph view of Prometheus

Template:Moons of Saturn Template:Saturn