[X] My Assistant

[Exploitcorporati...]

Padua Linea mosaic:

[belleraphon1]

Thanks for the comments MarcF, ugordon, and dilo....

Have to "kinda" agree. Wondered if the other image was taken at a slightly different exposure setting.

The CHARM presentation says the mass loading at Dione is an order of magnitude below what is seen at Enceladus. So I picture that as, perhaps, diffuse shedding of internal gassy molecules. It may not show up as a distinct plume. It may be distributed along the fracture systems......

What was the geometry of the Dione 16 encounter? What longitudes did that cover at closest approach?

Craig

[dilo]

Another couple of false color elaborations based on a sequence of increasing exposures, clear filter images:


(start images: N00064540/41/42)
First one associate an RGB channel to each image while in the second one I tried to highlight dimmest details.
To highlight the small difference between position angle of subsolar point and the faint glow, which seems slightly rotated toward left (the difference is about 20 deg, measured from Dione center).
Again, not enough to say if there is a weak plume or an artifact but seems interesting...

[JRehling]

Another couple of false color elaborations based on a sequence of increasing exposures, clear filter images:


(start images: N00064540/41/42)
First one associate an RGB channel to each image while in the second one I tried to highlight dimmest details.
To highlight the small difference between position angle of subsolar point and the faint glow, which seems slightly rotated toward left (the difference is about 20 deg, measured from Dione center).
Again, not enough to say if there is a weak plume or an artifact but seems interesting...

Just as a skeptical hypothesis, I wonder if this cometlike halo could be due to the summation of light coming from Dione plus some generalized light leak placed to the right.

[ugordan]

Just as a skeptical hypothesis, I wonder if this cometlike halo could be due to the summation of light coming from Dione plus some generalized light leak placed to the right.

That's probably about right. All Cassini images exhibit an ever-so-slight halo around bright objects. I don't know if it's an inherent "feature" of the narrow angle camera or residual haze traces or simply diffraction/PSF effects. Probably a bit of everything. In any case, if the Dionian hypothetical plumes are real and much weaker than Enceladean (as it's been suggested), about the only way to see them would be to occult the Sun so there's no illuminated crescent visible. No saturnshine would be a bonus, too. Even then, it's a question of the plumes themselves being in sunlight. That's a lot of geometry constraints.
AFAIK, this is not going to happen since Cassini already executed its dedicated Dione flyby and is left with only a couple of distant flybys in the primary mission. The chance of the geometry being such that Dione will occult the sun is miniscule. We're likely stuck with only hints of activity from the magnetometer readings.