PIA 12867: Bizarre Temperatures on Mimas
http://www.ciclops.org/view_media/31407 ... s_on_MimasThis figure illustrates the unexpected and bizarre pattern of daytime temperatures found on Saturn's small inner moon Mimas (396 kilometers, or 246 miles, in diameter). The data were obtained by the composite infrared spectrometer (CIRS) on NASA's Cassini spacecraft during the spacecraft's closest-ever look at Mimas on Feb. 13, 2010.
In the annotated version, the upper left image shows the expected distribution of temperatures. The white sun symbol shows the point where the sun is directly overhead, which is at midday close to the equator. Just as on Earth, the highest temperatures (shown in yellow) were expected to occur after midday, in the early afternoon.
The upper right image in the annotated version shows the completely different pattern that Cassini actually saw. Instead of the expected smoothly varying temperatures, this side of Mimas is divided into a warm part (on the left) and a cold part (on the right) with a sharp, v-shaped boundary between them. The warm part has typical temperatures near 92 Kelvin (minus 294 Fahrenheit), while typical temperatures on the cold part are about 77 Kelvin (minus 320 Fahrenheit). The cold part is probably colder because surface materials there have a greater thermal conductivity, so the sun's energy soaks into the subsurface instead of warming the surface itself. But why conductivity should vary so dramatically across the surface of Mimas is a mystery.
The lower two panels in the annotated version compare the temperature map to Mimas' appearance in ordinary visible light at the time of the observations. The map used to create this image is a mosaic of images taken by Cassini's imaging science subsystem cameras on previous flybys of Mimas. The cold side includes the giant Herschel Crater, which is a few degrees warmer than its surroundings. It's not yet known whether Herschel is responsible in some way for the larger region of cold temperatures that surrounds it.
1980s Video Icon Glows On Saturn Moon
GFSC: Goddard Instrument Aboard Cassini Spacecraft Sees 'Pac-Man' on Saturn Moon (2010 March 29)The highest-resolution-yet temperature map and images of Saturn's icy moon Mimas obtained by NASA's Cassini spacecraft reveal surprising patterns on the surface of the small moon, including unexpected hot regions that resemble "Pac-Man" eating a dot, and striking bands of light and dark in crater walls.
1980s Video Icon Glows on Saturn Moon
JPL (2010 March 29): Related Images
