On April 28, 1905, William H. Pickering, who had seven years earlier discovered Phoebe, announced the discovery of a tenth satellite of Saturn, which he promptly named Themis. The photographic plates on which it supposedly appeared, thirteen in all, spanned a period between April 17 and July 8, 1904. However, no other astronomer has ever confirmed Pickering's claim.
Proposed Properties[]
William H. Pickering attempted to compute an orbit for Themis, which showed a high inclination, a fairly large eccentricity, a Semi-major Axis slightly smaller than that of Hyperion's, and with an orbital period of 20.85 Days.
William also estimated the diameter of Themis to be 38 Miles (or 61.1551 Kilometers), which is based on his assumptions that Themis' Albedo was the same as Titan's albedo, and that Titan's diameter was 2,300 miles (3,701.49 kilometers). although, Titan's actual diameter is 3,199.726 miles (5,149.46 kilometers). the same assumptions led to him estimating the diameter of Phoebe to be 42 miles (67.5924 kilometers), which is far less than the actual diameter of Phoebe.
Existence[]
since its claimed discovery and observation, No other astronomer has been able to find Themis, nor having confirming William's claim. leading to its existence being ruled out. even with Cassini's arrival to the Mighty Ringed Planet, there was no sighting of Themis anywhere in plain sight.
An actual Tenth Satellite of Saturn would eventually be discovered in 1966, and would eventually be confirmed in 1980. this tenth satellite would be given the name, Janus.
Trivia[]
- Themis was accordingly spotted a year prior to its announced discovery in 1905. as it was apparently spotted in over 13 Photographic plates, which were taken in a time span to April 17th to July 8th, 1904.
- William H. Pickering actually had received the Lalande Prize by the French Academy of Sciences in 1906. mostly for his "discovery of the ninth or tenth satellite of Saturn".
- although, as mentioned above, Janus would eventually take that place as being the actual tenth satellite of Saturn.
- The name, "Themis", is also the name used for 24 Themis. an Asteroid located within the Asteroid Belt.
| Moons of Saturn | |
|---|---|
| Ring Shepherds | S/2009 S 1 • Pan • Daphnis • Atlas • Prometheus • Pandora |
| Co-orbitals | Janus • Epimetheus |
| G Ring | Aegaeon |
| Alkyonides | Methone • Pallene • Anthe |
| Inner Large Moons | Mimas • Enceladus • Tethys • (Telesto • Calypso) • Dione • (Helene • Polydeuces) |
| Outer Large Moons | Rhea • Titan • Hyperion • Iapetus |
| Inuit | Kiviuq • Paaliaq • Siarnaq • Ijiraq • S/2005 S 4 • S/2019 S 1 • S/2020 S 1 • Tarqeq • S/2004 S 31 • S/2019 S 14 • S/2020 S 3 • S/2019 S 6 |
| Gallic | Albiorix • Bebhionn • S/2007 S 8 • S/2004 S 29 • Erriapus • Tarvos • S/2020 S 4 |
| Norse | Phoebe • S/2006 S 20 • S/2006 S 9 • Skathi • S/2007 S 5 • S/2007 S 7 • S/2007 S 2 • S/2004 S 37 • S/2004 S 47 • S/2004 S 40 • S/2019 S 2 • S/2019 S 3 • S/2020 S 7 • Skoll • S/2020 S 2 • S/2019 S 4 • S/2004 S 41 • S/2004 S 42 • Hyrrokkin • Greip • S/2004 S 13 • S/2007 S 6 • Mundilfari • S/2006 S 1 • S/2004 S 43 • S/2006 S 10 • S/2019 S 5 • Gridr • Bergelmir • Jarnsaxa • Narvi • Suttungr • S/2007 S 3 • S/2004 S 44 • S/2004 S 45 • Hati • S/2004 S 17 • S/2006 S 11 • S/2004 S 12 • Eggther • S/2006 S 13 • S/2007 S 9 • S/2019 S 7 • S/2019 S 8 • Farbauti • Thrymr • Bestla • S/2019 S 9 • S/2004 S 46 • Angrboda • S/2019 S 11 • Aegir • Beli • S/2019 S 10 • S/2019 S 12 • Gerd • S/2019 S 13 • S/2006 S 14 • Gunnlod • S/2019 S 15 • S/2020 S 6 • S/2004 S 7 • S/2006 S 3 • S/2005 S 5 • Skrymir • S/2006 S 16 • S/2006 S 15 • S/2004 S 28 • S/2020 S 8 • Alvaldi • Kari • S/2004 S 48 • Geirrod • Fenrir • S/2004 S 50 • S/2006 S 17 • S/2004 S 49 • S/2019 S 17 • Surtur • S/2006 S 18 • Loge • Ymir • S/2019 S 19 • S/2004 S 21 • S/2019 S 18 • S/2004 S 39 • S/2019 S 16 • S/2004 S 53 • S/2004 S 36 • Thiazzi • S/2019 S 20 • S/2006 S 19 • S/2004 S 26 • Fornjot • S/2004 S 51 • S/2020 S 10 • S/2020 S 9 • S/2004 S 34 • S/2019 S 21 • S/2004 S 52
|
| Outlier Prograde Satellites | S/2006 S 12 • S/2004 S 24 |
| Spurious Moons | Chiron • Themis • S/2004 S 6 • S/2004 S 4 • S/2004 S 3 • Peggy |
| Hypothetical Bodies and other Hypothetical Objects | ||
|---|---|---|
| Hypothetical Planets | Inner Solar System | Enyo and Bellona • Vulcan • Antichthon • Nibiru • Theia • Phaeton • Planet V • Krypton |
| Outer Solar System | Fifth Giant • Unnamed ancient Super-earth • Triton’s Binary Partner • Planet 9 • Planet 10 • Tyche • Nemesis | |
| Hypothetical Moons | Inner Solar System | Disproven Moons of Mercury • Neith • Petit's moon • Waltemath's moons • Bagby's Moons • Moons of Pallas • Moon of Hebe |
| Outer Solar System | Chiron (hypothetical moon) • Chrysalis • Themis • Sedna I • Varuna I • Herschel's Moons | |
| Other Hypothetical Objects | Hypothetical Regions | Vulcanoid Belt • Hills Cloud • Oort Cloud |
| Hypotheses for Explanation of Occurrences | Hypotheses | Himalia Crash Theory • Iapetus' Ring System • The Nice Model & The Five-planet Nice Model |