The probe measured temperature differences across the object's surface and produced a map that looks just like the 1980s Pac-Man video games icon.

Scientists are unsure why Mimas should display such variations but say it is probably related to the diversity of textures in the surface materials.
Some textures may retain heat better than others, they explain.
Mimas is about 400km (250 miles) across. It has a distinctive scar called Herschel Crater which has led many to draw comparisons with the "Death Star" from the Star Wars movies.
The Cassini team says the creation of the crater itself might have played a key role in changing conditions across extensive regions of the moon's surface.
Cassini is a joint venture between the US space agency (Nasa), the European Space Agency (Esa) and the Italian Space Agency (ASI).
Its mission was recently extended through to 2017.

(from internet)