|click image to enlarge|
I wonder if this could perhaps be evidence of some sort of linear vent? The area along the line in the Aug 17 images appears rougher and more stones seems to be along the discoloration. Yet, when we see it again in the Sep 10 image, the area seems to be a lot more smoother, perhaps the smaller stones/boulders having been covered by the dust? Though, is there enough of a centripetal force for dust to settle?
Additionally, in the lower left of the right image, there does appear to be a round O shaped feature like a "Cheerio." The way the shadowing is seems to appear it has a pit veres the top or jagged edge of another boulder. Could this also be a vent? It does also seem to be there on the left as of the "Aug 17" image.
Update 1 - Sep 12
I rewatched the arrival conference video. http://wpc.50e6.edgecastcdn.net/8050E6/mmedia-http/download/public/videos/2014/08/010/1408_010_AR_EN.mp4
When they approached the comet and was testing out VIRTIS, they detected that the minimum mean temperature of the comet seems to be coming from the neck. We must then ask, why? We have seen images of direct sunlight, and it was getting direct sunlight at the time of the measurement. The max temperature came from a section on the "Body", the mid temp was on the "head", and minimum on the neck. The areas void of volatiles and are pores are the locations with the max temp. Does this mean there is either more volatiles and the area is less pores at the neck?
The Sep 2 image did show out gassing at the neck, which would seem to make sense if there were more volatiles there.
We also saw jets at the plains area on the underside of the "body". Im interested in measurements there, and at the large plains area on the crown of the "head" as seen in my comparison. It would seem due to the smoothness that there has been activity there.
Now, since they did post the VIRTIS map on the 8th. It does show that the top of the "head" which is A site landing target is very cool, so is the area around the neck, as well as the bottom of the "body" as very cool. The large plains on the body which Bill and I had recently conducted comparisons is also the other cool location.
These three locations seem to show the evidence of activity geologically. While these areas would be great landing sites terrain wise, they are areas of cold conditions. The only one of these where a landing was considered was "A", which may have lost out due to the revelation of the temperature. The landing sites seem to be in areas other then these active locations, which for a success of the mission, would make sense, though the question stands, will there be any data regarding the outgassing if you are not in an area not as active? Come November perhaps those sides of the body will be more active. But, as they are the hot areas, it would show that not only is it porous there, but either low or no volatiles. Which goes to show, IF there are volatiles at the dark regions, what do they composed of? We wont get this answer unless we are there to drill and find out.
Possible Landing Site "A" on the crown of the "head"
Update 2 - Sep 12
After further research,
The line/discoloration is visible on the arrival images as showing during the arrival webcast. To orientate you, he image compared to the above images are upside down.The O cheerio stucture is now seen at the upper right of the image now.