Anthe (moon)

Anthe /ˈænθiː/ is a very small natural satellite of Saturn lying between the orbits of Mimas and Enceladus. It is also known as Saturn XLIX; its provisional designation was S/2007 S 4. It is named after one of the Alkyonides; the name means flowery. It is the sixtieth confirmed moon of Saturn.^[5]

Anthe

Anthe is the ellipsoid in the center
Discovery
Discovered by	Cassini Imaging Team [1]
Discovery date	May 30, 2007
Designations
Designation	Saturn XLIX
Pronunciation	/ˈænθiː/[a]
Named after	Άνθη Anthē
Adjectives	Anthean /ænˈθiːən/
Orbital characteristics [2]
Semi-major axis	197,700 km
Eccentricity	0.0011
Orbital period (sidereal)	1.05089 d
Average orbital speed	13.824 km/s
Inclination	0.1° to Saturn's equator
Satellite of	Saturn
Group	Alkyonides
Physical characteristics
Dimensions	1.8 km [3]
Mean radius	0.9 km
Circumference	≈ 5.7 km
Surface area	10.18 km2
Volume	3 km3
Mass	1.5×1012 kg[4]
Mean density	0.5 g/cm3
Surface gravity	0.00012 m/s2 (0.12 mm/s2)
Escape velocity	≈ 0.56 m/s (≈ 2 km/h)
Synodic rotation period	assumed synchronous

The designation S/2007 S 4 was also accidentally and incorrectly used for a different Saturnian satellite discovered later. The published discovery was retracted a few hours later and republished the next day under the correct name of S/2007 S 5.

It was discovered by the Cassini Imaging Team^[1] in images taken on 30 May 2007.^[2] Once the discovery was made, a search of older Cassini images revealed it in observations from as far back as June 2004. It was first announced on 18 July 2007.^[2]

Discovery images of Anthe

Anthe is visibly affected by a perturbing 10:11 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 on a timescale of about 2 Earth years. The close proximity to the orbits of Pallene and Methone suggests that these moons may form a dynamical family.

Material blasted off Anthe by micrometeoroid impacts is thought to be the source of the Anthe Ring Arc, a faint partial ring about Saturn co-orbital with the moon first detected in June 2007.^[6][7]

References

Notes

1. This name is too new to appear in dictionaries, but the OED has the analogous rhodanthe /roʊˈdænθiː/ from the same root.

Citations

1. Cassini Imaging Team.
2. IAUC 8857.
3. ^{[dead link‍]}
4. ^{[dead link‍]}
5. Agle 2007.
6. Porco et al., 2008.
7. Hedman et al., 2009.

Sources

• "Cassini Imaging Science Team". Cassini Imaging Central Laboratory for OPerationS. Archived from the original on 2011-05-20. Retrieved 2012-01-01.
• Agle, D. C. (July 19, 2007). "Saturn Turns 60". Cassini Solstice Mission. JPL/NASA. Archived from the original on February 20, 2012. Retrieved 2012-01-01.
• Green, Daniel W. E. (July 18, 2007). "S/ 2007 S 4". IAU Circular. 8857. Retrieved 2012-01-01.
• Hedman, M. M.; Murray, C. D.; Cooper, N. J.; Tiscareno, M. S.; Beurle, K.; Evans, M. W.; Burns, J. A. (2008-11-25). "Three tenuous rings/arcs for three tiny moons". Icarus. 199 (2): 378–386. Bibcode:2009Icar..199..378H. doi:10.1016/j.icarus.2008.11.001. ISSN 0019-1035.
• Porco C. C.; et al. (2008-09-05). "More Ring Arcs for Saturn". Cassini Imaging Central Laboratory for Operations. Archived from the original on 2008-10-10. Retrieved 2008-09-05.

External links

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Media related to Anthe at Wikimedia Commons

• From Dark Obscurity... A Tiny New Saturnian Moon Comes To Light Archived 2011-02-02 at the Wayback Machine