Methone

Methone

Cassini image from 20 May 2012
Discovery
Discovered by	CICLOPS Team [1]
Discovery date	June 1, 2004
Designations
Pronunciation	/mɨˈθoʊniː/ mi-THOH-nee; or as Greek Μεθώνη
Adjective	Methonean
Orbital characteristics [2]
Epoch June 20, 2004 (JD 2453177.5)
Semi-major axis	194,440 ± 20 km
Eccentricity	0.0001
Orbital period	1.009573975 d [3]
Inclination	0.007 ± 0.003° (to Saturn's equator)
Satellite of	Saturn
Physical characteristics
Mean radius	1.6 ± 0.6 km [4]
Rotation period	synchronous
Axial tilt	zero

Methone is a very small natural satellite of Saturn lying between the orbits of Mimas and Enceladus.

Discovery and naming

Methone was first seen by the Cassini Imaging Team^[1][5][6] and given the temporary designation S/2004 S 1. Methone is also named Saturn XXXII (32). The Cassini–Huygens spacecraft has made two visits to Methone and its closest approach was made on May 20, 2012 with a minimum distance of 1,900 km from it.

The name Methone was approved by the IAU Working Group on Planetary System Nomenclature on January 21, 2005.^[7] It was ratified at the IAU General Assembly in 2006. Methone was one of the Alkyonides, the seven beautiful daughters of the Giant Alkyoneus.^[a]

Characteristics

In May 2012, the Cassini spacecraft obtained its first close-up photographs of Methone, revealing an egg-shaped moonlet with a remarkably smooth surface, with no visible craters.^[8]

Methone's orbit is visibly affected by a perturbing mean longitude resonance with the much larger Mimas. This causes its osculating orbital elements to vary with an amplitude of about 20 km in semi-major axis, and 5° in longitude on a timescale of about 450 days. Eccentricity also varies on different timescales between 0.0011 and 0.0037, and inclination between about 0.003° and 0.020°.^[2]

• 

  Discovery image of Methone on June 1, 2004^[9]

See also

• Methone Ring Arc

References

Explanatory

Citations

Sources

• "Cassini Imaging Science Team". Cassini Imaging Central Laboratory for OPerationS. http://ciclops.org/team/iss_team.php. Retrieved 2012-01-01. 
• Green, Daniel W. E. (August 16, 2004). "S/2004 S 1 and S/2004 S 2" (discovery). IAU Circular 8389. http://www.cbat.eps.harvard.edu/iauc/08300/08389.html. Retrieved 2012-01-01. 
• Green, Daniel W. E. (January 21, 2005). "S/2004 S 1 and S/2004 S 2" (naming the moon). IAU Circular 8471. http://www.cbat.eps.harvard.edu/iauc/08400/08471.html. Retrieved 2012-01-01. 
• "PIA06105: Cassini Uncovers New Moon". Photojournal. JPL/NASA. August 16, 2004. http://photojournal.jpl.nasa.gov/catalog/PIA06105. Retrieved 2012-01-01. 
• Lakdawalla, E. (2012-05-21). "Methone, an egg in Saturn orbit?". The Planetary Society web site. The Planetary Society. http://www.planetary.org/blogs/emily-lakdawalla/2012/05211206.html. Retrieved 2012-05-23. 
• Porco, C. C.; Baker, E.; Barbara, J.; Beurle, K.; Brahic, A.; Burns, J. A.; Charnoz, S.; Cooper, N. et al (February 25, 2005). "Cassini Imaging Science: Initial Results on Saturn's Rings and Small Satellites". Science 307 (5713): 1226–1236. doi:10.1126/science.1108056. PMID 15731439.  edit
• Spitale, J. N.; Jacobson, R. A.; Porco, C. C.; Owen, W. M., Jr. (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal 132 (2): 692–710. Bibcode 2006AJ....132..692S. doi:10.1086/505206.  edit
• Thomas, P. C. (July 2010). "Sizes, shapes, and derived properties of the saturnian satellites after the Cassini nominal mission". Icarus 208 (1): 395–401. Bibcode 2010Icar..208..395T. doi:10.1016/j.icarus.2010.01.025. http://www.ciclops.org/media/sp/2011/6794_16344_0.pdf.  edit

External links

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• Methone Profile by NASA's Solar System Exploration
• IAU Working Group for Planetary System Nomenclature