 Discovery image of S/2004 S 3 |
|
| Discovery | |
|---|---|
| Discovered by | CICLOPS Team [1] |
| Discovery date | June 21, 2004 |
| Orbital characteristics [2][3][4] | |
| Semi-major axis | 140,100–140,600 km |
| Eccentricity | < 0.002 [a] |
| Orbital period | 0.62 d |
| Inclination | close to zero |
| Satellite of | Saturn |
| Physical characteristics | |
| Mean radius | 1.5–2.5 km |
| 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 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. This suggests that it was a temporary clump of material that had disappeared by that time.[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 [edit]
Explanatory
- ^ Based on above semimajor axis range, and Spitale Jacobson et al. 2006
Citations
Sources
- "Cassini Imaging Science Team". Cassini Imaging Central Laboratory for OPerationS. 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. 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. 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.
External links [edit]
- 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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