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The exciting mystery of Enceladus' active south polar region continues to unfold as scientists make the correlation between geologically youthful surface fractures and anomalously warm temperatures recorded there.
These views show excess heat radiation from fissures near the south pole of the icy Saturnian moon. 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.
The images show two arrays of temperature readings across the surface of Enceladus, as measured by the Cassini Composite Infrared Spectrometer (CIRS), superimposed on images of the surface taken simultaneously by the Imaging Science Subsystem (ISS).
Surface temperatures in degrees Kelvin (K), derived from the intensity of infrared radiation detected by CIRS, are shown along with their formal uncertainties - although true uncertainties for temperatures below about 75 K are not easily described by a single number.
Enhanced thermal emission is seen in the vicinity of the prominent "tiger stripe" fissures discovered by ISS. In the first image (PIA07793), the excess emission is most strongly seen in the left-most CIRS field of view, which includes a fissure near the end of one of the tiger stripes. In the second image (PIA07794), the excess emission is near the center of the CIRS array, directly over a tiger stripe fissure. The peak temperatures, 86 K and 90 K respectively, are averages over the CIRS field of view, and other CIRS data suggest that much higher temperatures, up to at least 145 K, occur in narrow zones a few hundred meters wide along the tiger stripe fissures.
PIA07793 is centered near longitude 135 W, latitude 65 S and each square CIRS field of view is 17.5 kilometers (10.9 miles) across. PIA07794 was taken nearly three times closer to the moon and is centered near longitude 120 W, latitude 82 S, and each CIRS field of view is 6.0 kilometers (3.7 miles) across.
The Cassini narrow-angle camera images have been cropped and resized for presentation here.
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 imaging team consists of scientists from the US, England, France, and Germany. The composite infrared spectrometer team is based at NASA's Goddard Space Flight Center, Greenbelt, Md. The imaging operations center and team lead (Dr. C. Porco) are based at the Space Science Institute in Boulder, Colo.