S/2009 S 1
{{Short description|Small moonlet in Saturn's B ring}}
{{Infobox planet
| name = S/2009 S 1
| image = PIA11665 moonlet in B Ring cropped.jpg
| image_scale =
| caption = Cassini image of {{mp|S/2009 S 1}} as a bright dot casting a long shadow over Saturn's B Ring
| discoverer = Cassini Imaging Team
| discovered = 2009
| semimajor = {{val|116914|u=km}}
| period = {{cvt|0.4715|d|h}}
| eccentricity = ≈ 0.000
| inclination = ≈ 0.0
| satellite_of = Saturn
| group = outer B ring moonlet
| magnitude =
| rotation = assumed synchronous
}}
S/2009 S 1 is a moonlet embedded in the outer part of Saturn's B Ring, orbiting {{cvt|117,000|km|mi}} away from the planet. The moonlet was discovered by the Cassini Imaging Team during the Saturnian equinox event on 26 July 2009, when the Cassini spacecraft imaged the moonlet casting a {{cvt|36|km|mi}}-long shadow onto the B Ring. With a diameter of {{cvt|300|m|ft|sigfig=1}}, it is most likely a long-lived solid body, which would count it as the smallest and innermost known moon of Saturn.
Discovery
File:PIA11665 moonlet in B Ring.jpg is on the right.]]
{{mp|S/2009 S 1}} was first identified by the Cassini Imaging Team led by Carolyn Porco, in a single image taken by the Cassini spacecraft approximately {{cvt|296,000|km|mi}} from Saturn on 26 July 2009 11:30 UTC. The moonlet was discovered during Saturn's 2009 equinox, when it cast an approximately {{cvt|36|km|mi}}-long shadow on the planet's B ring.
Characteristics
Based on the shadow's width, the Cassini Imaging Team infer a diameter of {{cvt|300|m|ft|sigfig=1}} for {{mp|S/2009 S 1}}. The presence of a shadow suggests that the {{mp|S/2009 S 1}} is most likely a solid body large enough to have existed since the formation of the B ring. This particular moon is one of the smallest moons of Saturn that has been directly imaged.
{{mp|S/2009 S 1}} is located about {{cvt|650|km|mi}} interior to the edge of the B ring, corresponding to a radial distance of {{cvt|116,914 ± 17|km|mi|0}} from the center of Saturn. The moonlet protrudes {{cvt|150|sigfig=1|m|ft}} above the B ring plane, which has a vertical thickness of {{cvt|5|m|ft}} for comparison.
Although it is embedded in the B ring, {{mp|S/2009 S 1}} does not appear to produce extensive, propeller-shaped disturbance features unlike the propeller moonlets in Saturn's A ring. This may be because the B ring is very dense at the moonlet's location, which would hinder the formation of visible propeller gaps around the moonlet.
See also
References
{{reflist
| colwidth = 30em
| refs =
| title = Planetary Satellite Discovery Circumstances
| url = https://ssd.jpl.nasa.gov/sats/discovery.html
| publisher = Jet Propulsion Laboratory
| access-date = 28 March 2022}}
| title = Saturnian Satellite Fact Sheet
| url = https://nssdc.gsfc.nasa.gov/planetary/factsheet/saturniansatfact.html
| first = David R. |last = Williams
| work = Space Science Data Coordinated Archive
| publisher = NASA
| date = 15 October 2019
| access-date = 28 March 2022}}
| title = Cassini Imaging Science Team
| url = http://ciclops.org/team/iss_team.php
| work = Cassini Imaging Central Laboratory for OPerationS (CICLOPS)
| access-date = 2 January 2012}}
| editor = Green, D. W. E.
| first = C. | last = Porco
| author2 = the Cassini Imaging Team| name-list-style = amp
| title = S/2009 S1
| journal = IAU Circular
| date = 2 November 2009
| volume = 9091
| issue = 1
| page = 1 | url = http://ciclops.org/view_popup.php%3Fid=5926.html
| url-status = live
| archive-url = https://web.archive.org/web/20110611211632/http://ciclops.org/view_popup.php?id=5926&js=1
| archive-date = 11 June 2011
| access-date = 2 January 2012
| bibcode = 2009IAUC.9091....1P}}
| title = A Small Find Near Equinox
| url = https://solarsystem.nasa.gov/resources/14617/a-small-find-near-equinox/
| work = Cassini Solstice Mission
| publisher = Jet Propulsion Laboratory
| date = 7 August 2009
| archive-url = https://web.archive.org/web/20090809135913/http://saturn.jpl.nasa.gov/photos/imagedetails/index.cfm?imageId=3617
| url-status = dead
| archive-date = 9 August 2009
| access-date = 2 January 2012}}
| title = Image of Saturn-rings
| url = https://solarsystem.nasa.gov/raw_images/225230/
| work = Solar System Exploration
| publisher = NASA
| date = 26 July 2009
| archive-url = https://web.archive.org/web/20201127114327/https://solarsystem.nasa.gov/raw_images/225230/
| url-status = live
| archive-date = 27 November 2020
| access-date = 28 March 2022}}
|first1 = J. N. |last1 = Spitale
|first2 = C. C. |last2 = Porco
|title = Detection of Free Unstable Modes and Massive Bodies in Saturn's Outer B Ring
|url = https://iopscience.iop.org/article/10.1088/0004-6256/140/6/1747/pdf
|journal = The Astronomical Journal
|date = December 2010
|volume = 140
|issue = 6
|pages = 1747–1757
|doi = 10.1088/0004-6256/140/6/1747
|arxiv = 0912.3489
|bibcode = 2010AJ....140.1747S
|s2cid = 117319280}}
|first1 = Shugo |last1 = Michikoshi
|first2 = Eiichiro |last2 = Kokubo
|title = Formation of a Propeller Structure by a Moonlet in a Dense Planetary Ring
|url = https://iopscience.iop.org/article/10.1088/2041-8205/732/2/L23/pdf
|journal = The Astrophysical Journal Letters
|date = May 2011
|volume = 732
|issue = 2
|pages = 4
|id = L23
|doi = 10.1088/2041-8205/732/2/L23
|arxiv = 1104.0462
|bibcode = 2011ApJ...732L..23M
|s2cid = 18889201}}
}}
{{Moons of Saturn|state=uncollapsed}}
{{Saturn}}
{{DEFAULTSORT:S 2009 S1}}