[X] My Assistant

[jasedm]

The ciclops 'looking ahead' article for rev 60 (February 25th to March 7th) has just been posted, and alas no Titan or icy moons this revolution (bar a very distant wink at Tethys).
However, on the slate of observations is a 250 frame azimuthal scan of the Maxwell gap in the outer C ring, either side of periapsis.
This gap is around 220km across - more than enough to harbour a sizeable moon, and hence I suspect the reason for this observation.
AFAIK no scalloping either side of the gap has been detected thus far, but an irregular ringlet resides in the gap (as does one within the Encke division )
Anybody willing to predict yes or no to a new discovery? - any dynamicists here with sound reasons why one's unlikely to be found? does the gap coincide with any major resonances with other moons?

My guess is that no moon will be found (let's arbitrarily define 'moon' here as having a diameter 1km or greater) but I'd love to be proved wrong, and that Cassini is to find Saturn's 61st moon on the 61st orbit of the planet

[zvezdan]

First, let me correct few statements in this topic.

Two examples of an embedded moonlets (Pan and Daphnis) have their Hill spheres equal to their radius. An explanation for that was offered by Porco et al.
Such a moon maintains a gap that is several times their Hill sphere (factor of 3-10).

The outer moon resonances (either Linblad or vertical) can and do maintain some sharp ring-gap edges (examples: B ring outer edge by Mimas, A ring outer edge, bunch of such edges in C ring...).
There are also isolated ringlets created by strong resonances, for instance Titan 1:0 makes Titan ringlet in the C ring.

But the Maxwell gap is strange as there are no strong resonances anywhere close to it.
The ringlet inside the gap is eccentric and has variable width. Such a shape was neatly explained by Esposito et al.: the self-gravity of the ringlet keeps it eccentric and dictates the variable width (an eccentric ringlet without such effect would soon spread around, as particles with different distance to Saturn will have different precession rates due to the oblateness of Saturn and will make a circular spreaded ring).
However, that still leaves the Maxwell gap edges in question: what maintains them?
Well, there are many other edges which don't have an associated moon resonance. Are we going to propose un-observed embedded moonlet for each one of those? Plus, those moonlets would be deep inside the Roche zone - how would they survive the tides?
My 0.02$: it could be some interplay of ring (or isolated ringlets) self-gravity that helps confinement, similar to self-gravity keeping the eccentricity and shape of the Maxwell ringlet.