S/2004 S 4

Last updated
S/2004 S 4
Discovery
Discovered by CICLOPS Team  [1] [2]
Discovery dateJune 21, 2004
Orbital characteristics [3]
~140,100 km
Eccentricity unknown, small
~0.618 d
Inclination unknown, small
Satellite of Saturn
Group F Ring
Physical characteristics
Mean radius
~2 km
probably synchronous
unknown
Albedo unknown

    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. [2] The announcement was made on September 9, 2004. [4]

    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. [5]

    An interpretation where S/2004 S 3 and S/2004 S 4 are or were a single object on a F-ring crossing orbit is also possible. [4] 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.

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