S/2004 S 3
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 Discovery image of S/2004 S 3 |
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| Discovery | |
|---|---|
| Discovered by | Carl Murray / Cassini Imaging Science Team |
| Discovered on | 21 June 2004 |
| Orbital characteristics | |
| Semimajor axis | 140,100 − 140,600 km[1][2][3] |
| Eccentricity | < 0.002 [4] |
| Orbital period | 0.62 d |
| Inclination | close to zero |
| Is a satellite of | Saturn |
| Physical characteristics | |
| Mean diameter | 3-5 km |
| Rotation period | probably synchronous |
| Axial tilt | unknown |
| Albedo | unknown |
| Atmosphere | none |
S/2004 S 3 is the provisional designation of an object seen orbiting Saturn just beyond the outer strand of the F ring on 21 June 2004. It was first seen by Carl Murray of the Cassini Imaging Science Team in images taken by the Cassini-Huygens probe on June 21, 2004,[3] 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 15 November 2004 failed to recover the object. This suggests that it was a temporary clump of material that had disappeared by that time.[1]
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.
[edit] References
- ^ a b Spitale, J. N.; et al. (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal 132: 692. doi:.
- ^ IAUC 8432: Satellites and Rings of Saturn 2004 November 8 (claiming recovery of S/2004 S 3 on 17 October 2004, in conflict with the later (2006) Spitale et al.)
- ^ a b Martinez, C; Ormrod, G; and Finn, H.; Cassini Discovers Ring and One, Possibly Two, Objects at Saturn JPL news release (September 9, 2004)
- ^ Based on above semimajor axis range, and Spitale et al. (2006)
- ^ a b IAUC 8401: S/2004 S 3, S/2004 S 4, and R/2004 S 1 2004 September 9 (discovery)
[edit] External links
- Cassini-Huygens press release about discoveries around the F ring in 2004
- Cassini-Huygens Multimedia: The Clump/Moon Mystery September 5, 2005 (images of the clumps and/or moons seen around the F ring by Cassini cameras)
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