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Fornjot (moon)

From Wikipedia, the free encyclopedia
Fornjot
Fornjot imaged by the Cassini spacecraft in March 2014
Discovery
Discovered byScott S. Sheppard
David C. Jewitt
Jan T. Kleyna
Brian G. Marsden
Discovery dateDecember 2004
Designations
Designation
Saturn XLII
Pronunciation/ˈfɔːrnjt/
Icelandic: [ˈfɔ(r)tnˌjouːt]
Named after
Fornjót
S/2004 S 8
Orbital characteristics[1]
25108000 km
Eccentricity0.206
−1490.9 days
Inclination170.4°
Satellite ofSaturn
GroupNorse group
Physical characteristics[2][3]
6+50%
−30%
 km
(6.9 or 9.5) ± 0.4? h
Albedo0.06 (assumed)
Spectral type
r – i = 0.20 ± 0.09[4]
24.6
14.9

Fornjot /ˈfɔːrnjt/ 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]

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

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  1. ^ S.S. Sheppard (2019), Moons of Saturn, Carnegie Science, on line
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
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