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S/2004 S 3
	Discovery image of S/2004 S 3
Discovery
Discovered by	CICLOPS Team
Discovery date	June 21, 2004
Orbital characteristics
Semi-major axis	140,100–140,600 km
Eccentricity	< 0.002
Orbital period (sidereal)	0.62 d
Inclination	close to zero
Satellite of	Saturn
Group	F Ring
Physical characteristics
Mean radius	~2 km
Synodic rotation period	probably synchronous
Axial tilt	unknown
Albedo	unknown

S/2004 S 3 is the provisional designation of an object seen orbiting Saturn just beyond the outer strand of the F ring on June 21, 2004. It was discovered by the Cassini Imaging Science Team Archived 2011-05-20 at the Wayback Machine in images taken by the Cassini–Huygens probe on June 21, 2004^[4] and announced on September 9, 2004.^[5]

Despite later attempts to recover it, it has not been reliably sighted since. Notably, an imaging sequence covering an entire orbital period at 4 km resolution taken on November 15, 2004 failed to recover the object. The sequence should have been easily capable of detecting a moon of similar size, suggesting it to simply be a transient clump. An approximate linkage could be made of S/2004 S 3 to S/2004 S 4, and matched to two other detected clumps on other dates, but considering its non-detection in November, their relation is probably coincidental.^[2]

Another object, S/2004 S 4, was sighted nearby 5 hours later, but this time just inside the F Ring. Because of the differing localisation the second object was given a fresh designation, although their interpretation as a single object on a F-ring crossing orbit is also possible.^[5] Such an object might also be orbiting at a slightly different inclination to the F ring, thereby not actually passing through the ring material despite being seen both radially inward and outward of it.

If a solid object after all, S/2004 S 3 would be 3–5 km in diameter based on brightness, and might be a shepherd satellite for the outer edge of Saturn's F ring.

References

Explanatory

^ Based on above semimajor axis range, and Spitale Jacobson et al. 2006

Citations

^ CICLOPS Team.
^ ^a ^b Spitale Jacobson et al. 2006.
^ IAUC 8432.
^ ^a ^b Martinez, Ormrod & Finn 2004.
^ ^a ^b IAUC 8401.

Sources

"Cassini Imaging Science Team". Cassini Imaging Central Laboratory for OPerationS. Archived from the original on 2011-05-20. Retrieved 2012-01-01.
Green, Daniel W. E. (September 9, 2004). "S/2004 S 3, S/2004 S 4, and R/2004 S 1" (discovery). IAU Circular. 8401: 1. Bibcode:2004IAUC.8401....1P. Retrieved 2012-01-01.
Green, Daniel W. E. (November 8, 2004). "Satellites and Rings of Saturn". IAU Circular. 8432. Retrieved 2012-01-01. (claiming recovery of S/2004 S 3 on October 17, 2004 in conflict with the later Spitale Jacobson et al. 2006)
Martinez, Carolina; Ormrod, Gill; Finn, Heidi (September 9, 2004). "Cassini Discovers Ring and One, Possibly Two, Objects at Saturn". jpl.nasa.gov. NASA Jet Propulsion Laboratory. Archived from the original on 2006-10-21. Retrieved 2012-01-01.
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. S2CID 26603974.