I find difficult that being a chunk of ice or a meteorite; if you look it closely it has a kind of tail and, assuming the object has left that tail, it does not seem as if it was coming from Enceladus.
In my opinion it's just another cosmic ray hit.
John, i would say your hypothesis is possible. Large chunk of ice is more likely than an earthly atmospheric phenomonon.
i don't see enough in the image to tell me what the object in question is, but i will say it does not look like any artifact i have seen in previous images, processed or not. It sure looks like something is there.
I have to admit that I look forward to every image of Enceladus that is released from CASSINI. This one is a magnificent image of the geysers. I would question the meteorite statement though. To have a meteorite like that you would need an appreciable atmosphere which Enceladus does not possess. I would be more inclined to believe that this is a large chunk of ice being expelled from one of the stripes. Anyone agree?
John.
( My rating was '12'. )
At 10 O'clock (up and left) from the Enceladus eruptions appears to be a small meteorite.