The exciting mystery of an active south polar region on Saturn's icy moon
Enceladus continues to unfold as scientists make the correlation between
geologically youthful surface fractures and unusually warm temperatures.
This view shows excess heat radiation from cracks near the moon's south
pole. These warm fissures are the source of plumes of dust and gas seen
by multiple instruments on the Cassini spacecraft during its flyby of
Enceladus on July 14, 2005, as described in a series of papers in the
March 10, 2006, issue of the journal Science.
This image shows two arrays of temperature readings across the surface of
Enceladus, as measured by the Cassini composite infrared spectrometer,
superimposed on images of the surface taken simultaneously by the imaging
science subsystem.
Surface temperatures in Kelvin, derived from the intensity of infrared
radiation detected by composite infrared spectrometer, are shown along
with their formal uncertainties, although true uncertainties for
temperatures below about 75 Kelvin (minus 325 degrees Fahrenheit) are not
easily described by a single number.
Enhanced thermal emission is seen in the vicinity of the prominent "tiger
stripe" fissures discovered by the imaging cameras. In this image, the
excess emission is near the center of the composite infrared spectrometer
array, directly over a tiger stripe fissure. The peak temperatures, 86
Kelvin and 90 Kelvin (minus 305 and minus 298 degrees Fahrenheit)
respectively, are averages over the composite infrared spectrometer field
of view, and other composite and infrared spectrometer data suggest that
much higher temperatures, up to at least 145 Kelvin (minus 199 degrees
Fahrenheit), occur in narrow zones a few hundred meters wide along the
tiger stripe fissures. See PIA07793 for a related image.
This image was taken nearly three times closer to the moon and is centered
near longitude 120 west, latitude 82 south, and each composite infrared
spectrometer field of view is 6.0 kilometers (3.7 miles) across.
This Cassini narrow-angle camera image was cropped and resized for
presentation.
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 mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter was designed, developed and assembled at JPL. The
composite infrared spectrometer team is based at NASA's Goddard Space
Flight Center, Greenbelt, Md. The imaging operations center is based at
the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov. The composite infrared spectrometer
team homepage is http://cirs.gsfc.nasa.gov/. The imaging team
homepage is at http://ciclops.org