This image shows thermal radiation from the day and night sides of
Saturn's moon Phoebe, taken by the composite infrared spectrometer
onboard Cassini 1.8 hours before the spacecraft's closest approach to
Phoebe on June 11, 2004. The left-hand panel displays the image in
grayscale format, showing the brightness of Phoebe's radiation in the
wavelength range 15-17 microns, which is about 25 times the longest
wavelength visible to the naked eye. In the middle panel this brightness
is used to estimate the surface temperature distribution across Phoebe.
Temperatures are given in degrees Kelvin, and vary from a relatively
toasty 107 Kelvin (-267 Fahrenheit), in the late morning near the equator
(white, lower right), to less than 75 Kelvin (-324 Fahrenheit) in the
northern hemisphere in the pre-dawn hours (dark blue, upper left). The
"ragged edge" of Phoebe in this region is an instrumental artifact.
Temperatures are affected strongly by topography, as can be seen by
comparison with the visible-wavelength image (right). Some of the coldest
temperatures are found in the shadowed region inside the large depression
in the northern hemisphere (upper right).
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet Propulsion
Laboratory, a division of the California Institute of Technology in
Pasadena, manages the Cassini-Huygens mission for NASA's Office of Space
Science, Washington, D.C. The Cassini orbiter and its two onboard cameras
were designed, developed and assembled at JPL. The composite infrared
spectrometer team is based at NASA's Goddard Space Flight Center,
Greenbelt, Md.
For more information, about the Cassini-Huygens mission visit,
http://saturn.jpl.nasa.gov and the Cassini imaging team home page,
http//cirs.gsfc.nasa.gov/.
