Fornjot /ˈfɔːrnjoʊt/ or Saturn XLII is the outermost named moon 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 11 March 2005. It had the largest semi-major axis among all the known moons of Saturn[3]
 Fornjot imaged by the Cassini spacecraft in March 2014 | |
| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard David C. Jewitt Jan T. Kleyna Brian G. Marsden |
| Discovery date | December 2004 |
| Designations | |
Designation | Saturn XLII |
| Pronunciation | /ˈfɔːrnjoʊt/ Icelandic: [ˈfɔ(r)tnˌjouːt] |
Named after | Fornjót |
| S/2004 S 8 | |
| Orbital characteristics[1] | |
| 25108000 km | |
| Eccentricity | 0.206 |
| −1490.9 days | |
| Inclination | 170.4° |
| Satellite of | Saturn |
| Group | Norse group |
| Physical characteristics[2][3] | |
| 6+50% −30% km | |
| (6.9 or 9.5) ± 0.4? h | |
| Albedo | 0.06 (assumed) |
Spectral type | r – i = 0.20 ± 0.09[4] |
| 24.6 | |
| 14.9 | |
It is about 6 kilometres in diameter, and it orbits Saturn at an average distance of 23,609 Mm in 1491 d at an inclination of 168° to the ecliptic (160° to Saturn's equator) in a retrograde direction and with an eccentricity of 0.186. It is ambiguous whether the rotation period is 6.9 or 9.5±0.4 hours, but it is known to show very little variation in brightness and is probably very round in shape. It was also the faintest moon that was measured by Cassini–Huygens.[2][3]
Fornjot was named after Fornjót, a giant in Norse mythology.
References
edit- ^ S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
- ^ a b Denk, T.; Mottola, S. (2019). Cassini Observations of Saturn's Irregular Moons (PDF). 50th Lunar and Planetary Science Conference. Lunar and Planetary Institute.
- ^ a b c Denk, Tilmann; Mottola, Stefano; Tosi, Frederico; Bottke, William F.; Hamilton, Douglas P. (2018). "The Irregular Satellites of Saturn" (PDF). In Schenk, P.M.; Clark, R.N.; Howett, C.J.A.; Verbiscer, A.J.; Waite, J.H. (eds.). Enceladus and the Icy Moons of Saturn. Space Science Series. Vol. 322. Tucson, AZ: The University of Arizona Press. pp. 409–434. Bibcode:2018eims.book..409D. doi:10.2458/azu_uapress_9780816537075-ch020. ISBN 9780816537075.
- ^ Peña, José; Fuentes, Cesar (2022-05-17). "Colors of Irregular Satellites of Saturn with the Dark Energy Camera". The Astronomical Journal. 163 (6): 274. arXiv:2204.08391. Bibcode:2022AJ....163..274P. doi:10.3847/1538-3881/ac6258. ISSN 1538-3881.
External links
edit- Institute for Astronomy Saturn Satellite Data
- Jewitt's New Satellites of Saturn page
- IAUC 8523: New Satellites of Saturn May 4, 2005 (discovery)
- MPEC 2005-J13: Twelve New Satellites of Saturn May 3, 2005 (discovery and ephemeris)
- IAUC 8826: Satellites of Jupiter and Saturn April 5, 2007 (naming the moon)