Bestla (moon)

Summary

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
Bestla imaged by the Cassini spacecraft in September 2015
Discovery
Discovered byScott S. Sheppard
David C. Jewitt
Jan T. Kleyna
Brian G. Marsden
Discovery date2004
Designations
Designation
Saturn XXXIX
Pronunciation/ˈbɛstlə/
Named after
Bestla
S/2004 S 18
Orbital characteristics[1]
20337900 km
Eccentricity0.461
−1087.46 days
Inclination136.3°
Satellite ofSaturn
GroupNorse group
Physical characteristics
Dimensions15.56 × 7 × 5.98 km (modeled)[2]
Mean diameter
7+50%
−30%
 km
[3]
−14.6238±0.0001 h[3]
85°+5°
−15°
[4][a]
Albedo0.06 (assumed)[3]
23.8[4]
14.6[4]

Description edit

Bestla 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.[5] Like many of the outer irregular moons of the giant planets, Bestla's eccentricity may vary as a result of the Kozai mechanism. 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 edit

This moon was named in April 2007 after Bestla, a frost giantess from Norse mythology, who is a mother of Odin.

Notes edit

  1. ^ Assuming the north pole is the one pointing north of the invariable plane, in accordance with IAU standards.

References edit

  1. ^ a b Jacobson, R.A. (2007-06-28). "Planetary Satellite Mean Orbital Parameters". JPL/NASA. Retrieved 2008-01-19.
  2. ^ 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.
  3. ^ 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.
  4. ^ 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.
  5. ^ Brian G. Marsden (2005-05-03). "MPEC 2005-J13 : Twelve New Satellites of Saturn". Minor Planet Center. Retrieved 2008-01-19.

External links edit

  • Saturn's Known Satellites (by Scott S. Sheppard)
  • Jewitt's New Satellites of Saturn page
  • IAUC 8523: New Satellites of Saturn[permanent dead link] May 4, 2005 (discovery)
  • IAUC 8826: Satellites of Jupiter and Saturn[permanent dead link] April 5, 2007 (naming the moon)
  • raw Images