Cassini Encounters Enceladus: Background and the Discovery of a South Polar Hot Spot
Abstract
The Cassini spacecraft completed three close flybys of Saturn's enigmatic moon Enceladus between February and July 2005. On the third and closest flyby, on 14 July 2005, multiple Cassini instruments detected evidence for ongoing endogenic activity in a region centered on Enceladus' south pole. The polar region is the source of a plume of gas and dust, which probably emanates from prominent warm troughs seen on the surface. Cassini's Composite Infrared Spectrometer (CIRS) detected 3 to 7 gigawatts of thermal emission from the south polar troughs at temperatures up to 145 kelvin or higher, making Enceladus only the third known solid planetary body—after Earth and Io—that is sufficiently geologically active for its internal heat to be detected by remote sensing. If the plume is generated by the sublimation of water ice and if the sublimation source is visible to CIRS, then sublimation temperatures of at least 180 kelvin are required.
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We acknowledge the invaluable support of the entire Cassini science and engineering teams in making these observations possible. The work was supported by the NASA Cassini Project.
Information & Authors
Information
Published In
Science
Volume 311 • Issue 5766 • 10 March 2006
Pages: 1401 - 1405
History
Received: 21 October 2005
Accepted: 5 January 2006
Copyright
American Association for the Advancement of Science.
