Prometheus is an inner satellite of Saturn. It was discovered in 1980 (some time before October 25) from photos taken by the Voyager 1 probe, and was provisionally designated S/1980 S 27.
In late 1985 it was officially named after Prometheus, a Titan in Greek mythology. It is also designated Saturn XVI (16).[5] Pronunciation for Prometheus is 
/prɵˈmiːθiəs/, US dict: prō·mē′·thē·əs; Greek: Προμηθεύς.
This small moon is extremely elongated, measuring about 136 by 79 by 59 km. It has several ridges and valleys and a number of impact craters of about 20 km diameter are visible, but it is less cratered than nearby Pandora, Epimetheus and Janus. From its very low density and relatively high albedo, it seems likely that Prometheus is a very porous icy body. There is a lot of uncertainty in these values, however, and so this remains to be confirmed.
Prometheus acts as a shepherd satellite for the inner edge of Saturn's F Ring. Recent images from the Cassini probe show that the Promethean gravitational field creates kinks and knots in the F Ring as the moon 'steals' material from it. The orbit of Prometheus appears to be chaotic, as a consequence of a series of four 121:118 mean motion resonances with Pandora. The most appreciable changes in their orbits occur approximately every 6.2 years, when the periapsis of Pandora lines up with the apoapsis of Prometheus and the moons approach to within about 1400 km. Prometheus is itself a significant perturber of Atlas, with which it is in a 53:54 mean longitude resonance.
[edit] Selected images
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Prometheus pulling material from the F Ring
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Prometheus tugging kinks into the F Ring
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Cassini image (with moon's Saturn-facing end at lower right) reveals a surface covered with a blanket of fine material.
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Image from Jan. 27, 2010. Saturnshine illuminates the moon's night side. |
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Brightened version of same image
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[edit] Animations
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Prometheus collides with the F ring, pulls a streamer, and leaves behind a dark channel. 12 seconds 107 kbit/s
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Movie of Prometheus and the F Ring looped once. 5 seconds 48 kbit/s
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[edit] References
Citations
Sources
- Marsden, Brian G. (October 31, 1980). "Satellites of Saturn" (discovery). IAU Circular 3532. http://www.cbat.eps.harvard.edu/iauc/03500/03532.html. Retrieved 2011-12-29.
- Marsden, Brian G. (January 3, 1986). "Satellites of Saturn and Pluto" (naming the moon). IAU Circular 4157. http://www.cbat.eps.harvard.edu/iauc/04100/04157.html. Retrieved 2011-12-29.
- Renner, Stéfan F.; Sicardy, Bruno; French, Richard G. (March 2005). "Prometheus and Pandora: Masses and orbital positions during the Cassini tour". Icarus 174 (1): 230–240. Bibcode 2005Icar..174..230R. doi:10.1016/j.icarus.2004.09.005. edit
- Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M., Jr. (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal 132 (2): 692–710. Bibcode 2006AJ....132..692S. doi:10.1086/505206. edit
- Thomas, P. C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission". Icarus 208 (1): 395–401. Bibcode 2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025. http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf. edit
- USGS/IAU (July 21, 2006). "Planet and Satellite Names and Discoverers". Gazetteer of Planetary Nomenclature. USGS Astrogeology. http://planetarynames.wr.usgs.gov/Page/Planets#SaturnianSystem. Retrieved 2011-12-29.
[edit] External links
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Prometheus (moon)" article dated 2010-01-10, and does not reflect subsequent edits to the article. (
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/prɵˈmiːθiəs/, US dict: prō·mē′·thē·əs; Greek: Προμηθεύς.
Media related to Prometheus (moon) at Wikimedia Commons
