S/2004 S 4
|Discovered by||CICLOPS Team |
|Discovery date||June 21, 2004|
|Orbital characteristics |
|Semi-major axis||~140,100 km|
|Orbital period||~0.618 d|
|Mean radius||1.5–2.5 km|
|Rotation period||probably synchronous|
S/2004 S 4 is the provisional designation of an unconfirmed object seen orbiting Saturn within the inner strand of the F ring on June 21, 2004. It was spotted while J. N. Spitale was trying to confirm the orbit of another provisional object, S/2004 S 3 that was seen 5 hours earlier just exterior to the F ring. The announcement was made on September 9, 2004.
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.
An interpretation where S3 and S4 are or were a single object on a F-ring crossing orbit is also possible. 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 4 would be 3–5 km in diameter based on brightness.
- "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.
- 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.