... encounter with Saturn's icy moon Helene, beaming down raw images of the ... 4,330 miles (6,968 kilometers) of Helene's surface. It was the second closest approach to Helene of the entire mission.Cassini ...
The shape of this moonlet is a great surprise for me. Even after the surprises with Prometheus, Calypso and Helene I didn't expect it to be shaped almost perfectly like an egg ( taking as a fact that its shape is the same one in the small darkened area what I suppose to be like the lit one very probably ) . It is only 2 miles across.
Fantastic set of images of Helene.
Do we know if the surface is dust covered or comosed of icy grains, possibly sourced from the geysers of Enceladus or Saturn's rings in general?
Also Helene is only slightly larger than the Mars moon Phobos. Helene generally lacks impact craters accenpt for the side that is leading. Phobos seen at this resolution would be heavily cratered & grooved. Helene appears to lack both. Perhaps Helenequakes from impacts triggers these landslides & erases craters??? The surface gravity cannot be any more than 1/1,500th that on Earth.
Andrew R Brown.
I have not been here for a while. That is true, perhaps the flow lines could also indicate mass concentrations within Helene.
I also understood that the flow lines could also be from ice swept up from the geysers on Enceladus. The Tethys tojan moons Telesto & Calypso are also largely covered in fine ice & Calypso too shows hints of flowlines. Would be interesting to get a close up of Polydeuces if possible too, the other Dione trojan moon, the one that trails Dione. Polydeuces is only about 3.5 KM wide at most, so Helene is very much larger.
Another interesting mug shot of Helene, the leading Trojan moon of Dione. Helene is only 36 KM by 32 KM by 30 KM in size, where as Dione is 1,123 KM wide!!!! Mind you the trailling trojan moon Polydeuces is much smaller again, perhaps only 3 KM wide!!!!!!!!
What is interesting to see is that the three trojan moons seen up close to date (Helene for Dione as well as Telesto & Calypso for Tethys) is that thet all have smoother profiles & certainly Calypso & Helene display flow like features. Are they sweeping up ice crystals ejected from Enceladus's geysers???
Wow interesting views of Helene :) The curious flow like features seen from a far northern viewpoint are interesting, they appear to radiate from a point like hair growth from a crown on someones head!!!!
Just to say that around perikrone today, there was a non targetted Mimas pass, as well as that of Enceladus & Helene shortly after. Looking forward to seeing those images, Cassini did not pass that close to any of them, but more than close enough to reveal much new data & views from differing vantage points, than ever before.