Bestla /ˈbɛstlə/ or Saturn XXXIX is a retrograde irregular 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 13 December 2004 and 5 March 2005.
 Bestla imaged by the Cassini spacecraft in September 2015 | |
| Discovery | |
|---|---|
| Discovered by | Scott S. Sheppard David C. Jewitt Jan T. Kleyna Brian G. Marsden |
| Discovery date | 2004 |
| Designations | |
Designation | Saturn XXXIX |
| Pronunciation | /ˈbɛstlə/ |
Named after | Bestla |
| S/2004 S 18 | |
| Orbital characteristics[1] | |
| 20337900 km | |
| Eccentricity | 0.461 |
| −1087.46 days | |
| Inclination | 136.3° |
| Satellite of | Saturn |
| Group | Norse group |
| Physical characteristics | |
| Dimensions | 15.56 × 7 × 5.98 km (modeled)[2] |
| 7+50% −30% km[3] | |
| −14.6238±0.0001 h[3] | |
Pole ecliptic latitude | 85°+5° −15°[4][a] |
| Albedo | 0.06 (assumed)[3] |
Spectral type | g – r = 0.72 ± 0.07, r – i = 0.38 ± 0.07[5] |
| 23.8[4] | |
| 14.6[4] | |
Description
editBestla is about 7 kilometres in diameter, and orbits Saturn at an average distance of 20,337,900 km in 1087 days, at an inclination of 136° to the ecliptic, in a retrograde direction and with an eccentricity of 0.461.[1] Early observations from 2005 suggested that Bestla had a very high eccentricity of 0.77.[6] Like many of the outer irregular moons of the giant planets, Bestla's eccentricity may vary as a result of the Kozai mechanism.[citation needed] Bestla rotates in a retrograde direction and makes a full rotation every 14.6238±0.0001 hours.[3] Like Kiviuq, it is likely to be a contact binary or binary object, as its light curve has strong variation in brightness and a plateau-like maximum not seen in the other irregulars.[4]
Name
editThis moon was named in April 2007 after Bestla, a frost giantess from Norse mythology, who is a mother of Odin.
Notes
edit- ^ Assuming the north pole is the one pointing north of the invariable plane, in accordance with IAU standards.
References
edit- ^ a b Jacobson, R.A. (2007-06-28). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Retrieved 2008-01-19.
- ^ Melnikov, A. V.; Kopylova, Yu. G. (2022-12-01). "Simulation of the Rotational Dynamics and Light Curves of Saturn's Small Moons in the Fast Rotation Mode". Solar System Research. 56 (6). Springer Link: 403–410. doi:10.1134/S0038094622050045. ISSN 1608-3423.
- ^ a b c d 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 d 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.
- ^ Brian G. Marsden (2005-05-03). "MPEC 2005-J13 : Twelve New Satellites of Saturn". Minor Planet Center. Retrieved 2008-01-19.[dead link]
External links
edit- Saturn's Known Satellites (by Scott S. Sheppard)
- Jewitt's New Satellites of Saturn page
- IAUC 8523: New Satellites of Saturn May 4, 2005 (discovery)
- IAUC 8826: Satellites of Jupiter and Saturn April 5, 2007 (naming the moon)
- raw Images