S/2004 S 3
From Wikipedia, the free encyclopedia
 Discovery image of S/2004 S 3 |
|
| 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 S3 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 J.N. Spitale et al (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal 132: 692.
- ^ IAUC 8432
- ^ a b Cassini Discovers Ring and One, Possibly Two, Objects at Saturn JPL news release (2004)
- ^ Based on above semimajor axis range, and Spitale et al (2006)
- ^ a b IAUC 8401
[edit] External links
- Cassini-Huygens press release about discoveries around the F ring in 2004
- JPL news release
- IAUC 8432 − claiming recovery of S/2004 S 3 on 17 October 2004, in conflict with the later (2006) Spitale et al journal article by the Cassini Imaging Team.
- The Clump/Moon mystery Some 2005 Images of the clumps and/or moons seen around the F ring by Cassini cameras.
|
|
|
|---|---|
|
Generally listed in increasing distance from Saturn
|
|
| Ring shepherds | Pan · Daphnis · Atlas · Prometheus · S/2004 S 6? · S/2004 S 4? · S/2004 S 3? · Pandora |
| Co-orbitals | Epimetheus · Janus |
| Inner large and Trojan | Mimas · Methone · Pallene · Enceladus · Tethys (trojans Telesto, Calypso) · Dione (trojans Helene, Polydeuces) |
| Outer large | Rhea · Titan · Hyperion · Iapetus |
| Inuit group | Kiviuq · Ijiraq · Paaliaq · Siarnaq |
| Norse group | Phoebe · Skathi · Skoll · S/2004 S 13 · S/2006 S 4 · Hyrokkin · Mundilfari · S/2006 S 6 · S/2006 S 1 · S/2004 S 17 · Narvi · Bergelmir · Aegir · Suttungr · S/2004 S 12 · Bestla · Farbauti · Hati · S/2004 S 7 · Thrymr · S/2006 S 3 · Surtur · Kari · Fenrir · Ymir · Loge · Fornjot |
| Gallic group | Albiorix · Bebhionn · Erriapo · Tarvos |
