Atlas (moon)

Template:Short description {{#invoke:infobox|infoboxTemplate | class = vcard | titleclass = fn org | title = Atlas | image = {{#invoke:InfoboxImage|InfoboxImage|image=Atlas color PIA21449.png|upright={{#if:||1.1}}|alt=}} | caption = Color photo taken by Cassini on 12 April 2017 | 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 = 0.4 | label94 = Temperature | data94 = ≈ 81 K

| data100 = {{#if:|

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| header110 = Atmosphere

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Atlas is an inner satellite of Saturn which was discovered by Richard Terrile in 1980 from Voyager photos and was designated Template:Nowrap.Template:Sfn In 1983 it was officially named after Atlas of Greek mythology, because it "holds the rings on its shoulders" like the Titan Atlas held the sky up above the Earth.Template:Sfn It is also designated Template:Nowrap.

Atlas is the closest satellite to the sharp outer edge of the A ring, and was long thought to be a shepherd satellite for this ring. However, now it is known that the outer edge of the ring is instead maintained by a 7:6 orbital resonance with the larger but more distant moons Janus and Epimetheus.Template:Sfn In 2004 a faint, thin ring, temporarily designated Template:Nowrap, was discovered in the Atlantean orbit.Template:Sfn

High-resolution images taken in June 2005 by Cassini revealed Atlas to have a roughly spherical centre surrounded by a large, smooth equatorial ridge. The most likely explanation for this unusual and prominent structure is that ring material swept up by the moon accumulates on the moon, with a strong preference for the equator due to the ring's thinness. The size of the equatorial ridge is comparable with the expected Roche lobe of the moon, which means that for any additional particles impacting the equator, the centrifugal force will nearly overcome Atlas's tiny gravity, and they will probably be lost.Template:Sfn

Atlas is significantly perturbed by Prometheus and to a lesser degree by Pandora, leading to excursions in longitude of up to 600 km (~0.25°) away from the precessing Keplerian orbit with a rough period of about 3 years. Because the orbits of Prometheus and Pandora are chaotic, it is suspected that Atlas's may be as well.Template:Sfn

GalleryEdit

Cassini Atlas N00084634 CL.png

Atlas from above its south pole (June 12, 2007)
Atlas Rev09.2x.jpg

Atlas - Cassini
(June 8, 2005).
Atlas with rings.jpg

Atlas - A and F rings
(June 30, 2006).
PIA17206-SaturnMoon-Atlas-Flyby-20151206.jpg

Atlas near the A ring
(December 6, 2015).
F Ring and Atlas PIA10448.jpg

Atlas near the F ring
(May 9, 2005).

NotesEdit

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ReferencesEdit

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External linksEdit

Template:Sister project Template:Spoken Wikipedia

Template:Moons of Saturn Template:Saturn