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The timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. Each object is listed in chronological order of its discovery, identified through its various designations, and the discoverer(s) listed. Historically the naming of moons did not always match the times of their discovery. Traditionally, the discoverer enjoys the privilege of naming the new object; however, some neglected to do so or actively declined. The issue arose nearly as soon as planetary satellites were discovered: Galileo referred to the four main satellites of Jupiter using numbers while the names suggested by his rival Simon Marius gradually gained universal acceptance. The International Astronomical Union (IAU) eventually started officially approving names in the late 1970s. With the explosion of discoveries in the 21st century, new moons have once again started to be left unnamed even after their numbering, beginning with Jupiter LI and Jupiter LII in 2010.
The moons of Saturn are numerous and diverse, ranging from tiny moonlets only tens of meters across to enormous Titan, which is larger than the planet Mercury. As of 2023, Saturn has 83 known moons with confirmed orbits that are not embedded in its rings—of which only 13 have diameters greater than 50 kilometers—as well as dense rings that contain millions of embedded moonlets and innumerable smaller ring particles. Seven Saturnian moons are large enough to have collapsed into a relaxed, ellipsoidal shape, though only one or two of those, Titan and possibly Rhea, are currently in hydrostatic equilibrium. Particularly notable among Saturn's moons are Titan, the second-largest moon in the Solar System, with a nitrogen-rich Earth-like atmosphere and a landscape featuring dry river networks and hydrocarbon lakes, Enceladus, which emits jets of gas and dust from its south-polar region, and Iapetus, with its contrasting black and white hemispheres.
Scott Sander Sheppard is an American astronomer and a discoverer of numerous moons, comets and minor planets in the outer Solar System.
S/2004 S 7 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 4 May 2005 from observations taken between 12 December 2004 and 8 March 2005.
S/2004 S 12 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 4 May 2005 from observations taken between 12 December 2004 and 9 March 2005.
S/2004 S 17 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 4 May 2005 from observations taken between 13 December 2004 and 5 March 2005.
S/2004 S 13 is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, Jan Kleyna, and Brian G. Marsden on 4 May 2005 from observations taken between 12 December 2004 and 9 March 2005.
The Norse group is a large group of retrograde irregular satellites of Saturn. Their semi-major axes range between 12 and 24 Gm, their inclinations between 136° and 175° and their eccentricities between 0.13 and 0.77. Unlike for the Inuit and Gallic groups, the orbital parameters are widely dispersed and group is likely to be composed from a number of subgroups with more homogenous orbital and physical parameters. For example, the satellites with inclinations around 174 degrees alone are thought to comprise at least two subgroups. Eight other moons form the Skathi subgroup. Their semi-major axes range between 15 and 20 Gm, their inclinations between 147° and 158°. Narvi forms a separate subgroup with Bestla. The International Astronomical Union (IAU) reserves names taken from Norse mythology for these moons. The exception is Phoebe, the largest, which was discovered long before the others.
Gridr, originally known as S/2004 S 20, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 22, 2007. It was given its permanent designation in June 2021. On 24 August 2022, it was officially named after Gríðr, a jötunn in Norse mythology. She is the mother of Víðarr the silent and the consort of Odin. She warned Thor about the treachery of Geirröðr and equipped him with her belt of strength, her iron glove, and her staff Gríðarvöl (Gríðr's-staff).
Angrboda, provisionally known as S/2004 S 22, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and February 1, 2006. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Angrboða, a jötunn in Norse mythology. She is the consort of Loki and the mother of the wolf Fenrir, the Midgard serpent Jörmungandr, and the ruler of the dead Hel.
Skrymir, provisionally known as S/2004 S 23, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 22, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Útgarða-Loki. He is a jötunn from Norse mythology and master of illusions.
S/2004 S 24 is a natural satellite of Saturn, and the outermost known prograde satellite. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 22, 2007.
Gerd, provisionally known as S/2004 S 25, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 22, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Gerðr, a jötunn from Norse mythology. She is the wife of Freyr and the personification of fertile soil.
Saturn LVIII, provisionally known as S/2004 S 26, is the outermost known natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 21, 2007. It was given its permanent designation in August 2021.
Eggther, provisionally known as S/2004 S 27, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 21, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Eggþér, a jötunn from Norse mythology. He is the herder of the female jötunn who lives in Járnviðr (Ironwood) and raises monstrous wolves. In the poem Völuspá, Eggþér is described as sitting on a mound and joyfully striking his harp while the red rooster Fjalarr begins to crow to herald the onset of Ragnarök.
Beli, provisionally known as S/2004 S 30, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 7, 2019 from observations taken between December 12, 2004 and March 21, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was named after Beli, a jötunn from Norse mythology. He is killed by Freyr with the antler of a hart (stag). According to John Lindow, the myth of Beli is partially lost. Some scholars suggest that he may be the brother of Freyr's wife Gerðr, although this is uncertain.
Gunnlod, provisionally known as S/2004 S 32, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019 from observations taken between December 12, 2004 and January 19, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Gunnlǫð, a jötunn from Norse mythology. She is the daughter of Suttungr and guarded the mead of poetry for him. But Odin in the form of a snake gained access to the chamber in Hnitbjorg where the mead was kept, seduced Gunnlǫð, and slept with her for three nights. In return Gunnlǫð allowed Odin three drinks of the mead, and he then immediately flew out of the cavern in the form of an eagle.
Saturn LXIV, provisionally known as S/2004 S 34, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019 from observations taken between December 12, 2004 and March 21, 2007. It was given its permanent designation in August 2021.
Alvaldi, provisionally known as S/2004 S 35, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019 from observations taken between December 12, 2004 and February 25, 2006. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Alvaldi, a jötunn from Norse mythology. He was very rich in gold, and when he died his sons divided his inheritance by taking a mouthful each.
Geirrod, provisionally known as S/2004 S 38, is a natural satellite of Saturn. Its discovery was announced by Scott S. Sheppard, David C. Jewitt, and Jan Kleyna on October 8, 2019 from observations taken between December 12, 2004 and March 22, 2007. It was given its permanent designation in August 2021. On 24 August 2022, it was officially named after Geirröðr, a jötunn from Norse mythology. He is an enemy of Thor and is killed by him.
References
- ↑ Discovery Circumstances from JPL
- 1 2 S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
- 1 2 "MPEC 2019-T155 : S/2004 S 33". minorplanetcenter.net. Retrieved 8 October 2019.
- ↑ "M.P.C. 133821" (PDF). Minor Planet Center. International Astronomical Union. 10 August 2021. Retrieved 21 August 2021.
- ↑ "Names Approved for 10 Small Satellites of Saturn". usgs.gov. USGS. 24 August 2022. Retrieved 30 August 2022.
- ↑ "Planet and Satellite Names and Discoverers". usgs.gov. IAU WGPSN. Retrieved 30 August 2022.
