New Dione Image: Older Southern Fractures?

CICLOPS released today this processed view of Dione on August 1. This image was taken from a distance of 269,000 km and has a resolution of 2 km/pixel. The wispy terrain of Dione can be seen toward the top with Padua Linea running from top center to right and Palantine Linea running along the terminator at left. In contrast to these relatively sharp fractures, the fracture systems near the south pole, just to the left of the large impact basin, have relatively subdued topography and are probably older than the fractures that make up the wispy terrrain. The radial feature near the center of the disk, Cassandra, was thought to be caused by a ray crater, but analysis of the topography associated with the feature now shows that Cassandra likely has a tectonic origin.

Note the two craters just to the left of Cassandra. These craters have a similar shape to Ali Baba and Aladdin craters on Enceladus, perhaps indicating local heating in that region of Dione, in order to produce the viscous relaxation we observe.