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Prometheus (moon)

{{Short description|Moon of Saturn}}

{{For|the asteroid|1809 Prometheus}}

{{Infobox planet

| name = Prometheus

| image = Prometheus 12-26-09b.jpg

| image_scale =

| caption = Prometheus image from Cassini (December 26, 2009)

| pronounced = {{IPAc-en|p|r|ə|ˈ|m|iː|θ|iː|ə|s}}{{Cite encyclopedia |url=http://www.lexico.com/definition/Prometheus |archive-url=https://web.archive.org/web/20200320063552/https://www.lexico.com/definition/prometheus |url-status=dead |archive-date=March 20, 2020 |title=Prometheus |dictionary=Lexico UK English Dictionary |publisher=Oxford University Press}}

| adjective = Promethean, -ian {{IPAc-en|p|r|ə|ˈ|m|iː|θ|iː|ə|n}}{{Cite encyclopedia |url=http://www.lexico.com/definition/Promethean |archive-url=https://web.archive.org/web/20200320063559/https://www.lexico.com/definition/promethean |url-status=dead |archive-date=March 20, 2020 |title=Promethean |dictionary=Lexico UK English Dictionary UK English Dictionary |publisher=Oxford University Press}}

| named_after = Προμηθεύς Promētheys

| mpc_name = Saturn XVI

| discoverer = Stewart A. Collins
D. Carlson
Voyager 1

| discovered = October, 1980

| orbit_ref = {{sfn|Spitale Jacobson et al.|2006}}

| epoch = 31 December 2003 (JD {{val|2453005.5}})

| semimajor = {{val|139380|10|u=km}}

| eccentricity = {{val|0.0022}}

| period = {{val|0.612990038|u=d}}

| inclination = {{val|0.008|0.004|u=°}} to Saturn's equator

| satellite_of = Saturn

| group = Inner shepherd moon of the F Ring

| dimensions = {{val|137.0|x|81.0|x|56.2}} km
(± {{val|1.0|x|2.8|x|0.8}} km){{sfn|Thomas & Helfenstein|2020}}{{rp|page=2}}

| mean_diameter = {{val|85.6|1.4|u=km}}{{sfn|Thomas & Helfenstein|2020}}{{rp|page=2}}

| volume = {{val|327740|1710|u=km3}}{{sfn|Lainey et al.|2023}}{{rp|page=4}}

| mass = {{val|1.59720|0.00072|e=17|u=kg}}{{efn|Calculated from the standard gravitational parameter GM {{=}} {{val|1.06602|0.00048|e=-2|u=km3·s–2}} given by Lainey et al. (2023), divided by the gravitational constant G {{=}} {{val|6.6743|e=-2|u=km3·kg–1·s–2}}.{{sfn|Lainey et al.|2023}}}}

| density = {{val|0.4873|0.0026|u=g/cm3}}{{sfn|Lainey et al.|2023}}{{rp|page=4}}

| surface_grav = {{val|0.0007|-|0.0056|u=m/s2}}{{sfn|Thomas & Helfenstein|2020}}{{rp|page=3}}

| escape_velocity = {{V2|1.59720e-4|68.5|3}} km/s at longest axis
to {{V2|1.59720e-4|28.1|3}} km/s at poles

| rotation = synchronous

| axial_tilt = zero

| albedo = 0.6

| single_temperature = ≈ 74 K

}}

Prometheus {{IPAc-en|p|r|ə|ˈ|m|iː|θ|iː|ə|s}} 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 {{nowrap|S/1980 S 27}}.{{sfn|IAUC 3532}}

In late 1985 it was officially named after Prometheus, a Titan in Greek mythology.{{sfn|IAUC 4157}} It is also designated {{nowrap|Saturn XVI}}.{{sfn|USGS: Planet and Satellite Names and Discoverers}}

Prometheus is extremely elongated, measuring approximately {{convert|137 x 81 x 56|km|mi|abbr=on}}. It has several ridges and valleys and a number of impact craters of about {{convert|20|km|mi|abbr=on}} 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 moons

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.{{cite web

| last = Lakdawalla | first = E. | author-link = Emily Lakdawalla

| title = On the masses and motions of mini-moons: Pandora's not a "shepherd," but Prometheus still is

| publisher = Planetary Society | date = 2014-07-05

| url = http://www.planetary.org/blogs/emily-lakdawalla/2014/07010001-ringmoons-shepherds.html

| access-date = 2015-04-17 }}{{cite journal|last1=Cuzzi|first1=J. N.|last2=Whizin|first2=A. D.|last3=Hogan|first3=R. C.|last4=Dobrovolskis|first4=A. R.|last5=Dones|first5=L. |last6=Showalter|first6=M. R.|last7=Colwell|first7=J. E.|last8=Scargle|first8=J. D.|title=Saturn's F Ring core: Calm in the midst of chaos|journal=Icarus|volume=232|date=April 2014|pages=157–175|issn=0019-1035|doi=10.1016/j.icarus.2013.12.027|bibcode = 2014Icar..232..157C }}

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.{{sfn|Renner et al. 2005}} The most appreciable changes in their orbits occur approximately every 6.2 years,{{sfn|Spitale Jacobson et al.|2006}} 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.{{sfn|Spitale Jacobson et al.|2006}}

{{clear}}

Selected images

{{gallery

| title =

| width = 200

| File:Prometheus's effect on the F Ring.jpg|Prometheus pulling material from the F Ring

| File:Prometheus tugging on F Ring PIA09909.jpg|Prometheus tugging kinks into the F Ring

| File:Prometheus - Voyager 2.jpg|Voyager 2 (August 25, 1981) image

| File:Prometheus 12-26-09a.jpg|Cassini image (with moon's Saturn-facing end at lower right) reveals a surface covered with a blanket of fine material.

| File:PIA12593 Prometheus.jpg|Image from Jan. 27, 2010. Saturnshine illuminates the moon's night side.

| File:PIA12593 Prometheus2.jpg|Brightened version of same image

| File:PIA17207-SaturnMoon-Prometheus-20151206.jpg|Prometheus flyby
(December 6, 2015)

}}

Animations

{{gallery

| title =

| width = 400

| File:Prometheus collides with F ring PIA08397 ff025.ogv|Prometheus collides with the F ring, pulls a streamer, and leaves behind a dark channel. 12 seconds 107 kbit/s

| File:Prometheus F ring from PIA08262 fr25 twice.ogv|Movie of Prometheus and the F Ring looped once. 5 seconds 48 kbit/s

}}

Notes

{{notelist}}

References

= Citations =

{{reflist}}

= Sources =

  • {{cite journal

| last = Marsden

| first = Brian G.

| title = Satellites of Saturn

| date = October 31, 1980

| format = discovery

| journal = IAU Circular

| issue = 3532

| url = http://www.cbat.eps.harvard.edu/iauc/03500/03532.html

| access-date = 2011-12-29

| ref = {{sfnRef|IAUC 3532}}

}}

  • {{cite journal

| last = Marsden

| first = Brian G.

| title = Satellites of Saturn and Pluto

| date = January 3, 1986

| format = naming the moon

| journal = IAU Circular

| issue = 4157

| url = http://www.cbat.eps.harvard.edu/iauc/04100/04157.html

| access-date = 2011-12-29

| ref = {{sfnRef|IAUC 4157}}

}}

  • {{cite journal| doi = 10.1016/j.icarus.2004.09.005| last1 = Renner| first1 = Stéfan F.| last2 = Sicardy| first2 = Bruno| last3 = French| first3 = Richard G.| date = March 2005| title = Prometheus and Pandora: Masses and orbital positions during the Cassini tour| journal = Icarus| volume = 174| issue = 1| pages = 230–240| bibcode=2005Icar..174..230R| ref = {{sfnRef|Renner et al. 2005}}}}
  • {{cite journal| doi = 10.1086/505206| last1 = Spitale| first1 = J. N.| last2 = Jacobson| first2 = R. A.| last3 = Porco| first3 = C. C.| last4 = Owen| first4 = W. M. Jr. | year = 2006| title = The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations| journal = The Astronomical Journal| volume = 132| issue = 2| pages = 692–710| bibcode = 2006AJ....132..692S| ref = {{sfnRef|Spitale Jacobson et al.|2006}}| doi-access = free}}
  • {{cite journal| doi = 10.1016/j.icarus.2010.01.025| last1 = Thomas| first1 = P. C.| date = July 2010| title = Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission| journal = Icarus| volume = 208| issue = 1| pages = 395–401| url = http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf| bibcode = 2010Icar..208..395T| access-date = 2015-09-04| archive-date = 2018-12-23| archive-url = https://web.archive.org/web/20181223003125/http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf| url-status = dead}}
  • {{cite web

| author = USGS/IAU

| title = Planet and Satellite Names and Discoverers

| date = July 21, 2006

| publisher = USGS Astrogeology

| work = Gazetteer of Planetary Nomenclature

| url = http://planetarynames.wr.usgs.gov/Page/Planets#SaturnianSystem

| access-date = 2011-12-29

| ref = {{sfnRef|USGS: Planet and Satellite Names and Discoverers}}

}}

  • {{cite journal

|ref = {{sfnRef|Thomas & Helfenstein|2020}}

|first1 = P. C. |last1 = Thomas

|first2 = P. |last2 = Helfenstein

|title = The small inner satellites of Saturn: Shapes, structures and some implications

|journal = Icarus

|date = July 2020

|volume = 344

|id = 113355

|pages = 20

|doi = 10.1016/j.icarus.2019.06.016

|bibcode = 2020Icar..34413355T|s2cid = 197474587 }}

  • {{cite journal

|ref = {{sfnRef|Lainey et al.|2023}}

|first1 = V. |last1 = Lainey

|first2 = N. |last2 = Rambaux

|first3 = N. |last3 = Cooper

|first4 = R. |last4 = Dahoumane

|first5 = Q. |last5 = Zhang

|title = Characterising the interior of five inner Saturnian moons using Cassini ISS data

|journal = Astronomy & Astrophysics

|date = February 2023

|volume = 670

|id = L25

|pages = 6

|doi-access = free

|doi = 10.1051/0004-6361/202244757

|bibcode = 2023A&A...670L..25L}}

External links

{{Spoken Wikipedia|Prometheus (moon).ogg|date=2010-01-10}}

{{commons category-inline|bullet=none}}

  • {{cite web |title=Cassini–Huygens: Multimedia-Videos / Soft Collision |publisher=NASA |url=http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=163 |archive-url=https://web.archive.org/web/20071029205038/http://saturn.jpl.nasa.gov/multimedia/videos/video-details.cfm?videoID=163 |archive-date=29 October 2007 |quote=Prometheus slowly collides with the diffuse inner edge of Saturn's F ring ... pulls a streamer of material from the ring and leaves behind a dark channel.}}
  • [https://web.archive.org/web/20070609144848/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Sat_Prometheus Prometheus Profile] at [http://solarsystem.nasa.gov NASA's Solar System Exploration site]
  • [https://web.archive.org/web/20060830121943/http://www.planetary.org/explore/topics/saturn/prometheus.html The Planetary Society: Prometheus]
  • [http://ciclops.org/view/6133/Prometheus_Popping_in_3-D 3-D] anaglyph view of Prometheus

{{Moons of Saturn}}

{{Saturn}}

{{DEFAULTSORT:Prometheus (Moon)}}

Category:Moons of Saturn

Category:Astronomical objects discovered in 1980

Category:Articles containing video clips

Category:Prometheus

Category:Discoveries by Stewart A. Collins

Category:Moons with a prograde orbit