Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 10 March 2006:
Vol. 311. no. 5766, pp. 1401 - 1405
DOI: 10.1126/science.1121661
Prev | Table of Contents | Next

Research Articles

Cassini Encounters Enceladus: Background and the Discovery of a South Polar Hot Spot

J. R. Spencer,1* J. C. Pearl,2 M. Segura,2 F. M. Flasar,2 A. Mamoutkine,2 P. Romani,2 B. J. Buratti,3 A. R. Hendrix,3 L. J. Spilker,3 R. M. C. Lopes3

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.

1 Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 400, Boulder, CO 80302, USA.
2 NASA Goddard Spaceflight Center, Code 693, Greenbelt, MD 20771, USA.
3 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA.

* To whom correspondence should be addressed. E-mail: spencer{at}boulder.swri.edu

Read the Full Text


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
From the Cover: Unified model of tectonics and heat transport in a frigid Enceladus.
G. Gioia, P. Chakraborty, S. Marshak, and S. W. Kieffer (2007)
PNAS 104, 13578-13581
   Abstract »    Full Text »    PDF »
A Clathrate Reservoir Hypothesis for Enceladus' South Polar Plume.
S. W. Kieffer, X. Lu, C. M. Bethke, J. R. Spencer, S. Marshak, and A. Navrotsky (2006)
Science 314, 1764-1766
   Abstract »    Full Text »    PDF »
Enceladus: cosmic gymnast, volatile miniworld..
J. S. Kargel (2006)
Science 311, 1389-1391
   Abstract »    Full Text »    PDF »
Does Enceladus govern magnetospheric dynamics at Saturn?.
M. G. Kivelson (2006)
Science 311, 1391-1392
   Abstract »    Full Text »    PDF »
Cassini observes the active south pole of Enceladus..
C. C. Porco, P. Helfenstein, P. C. Thomas, A. P. Ingersoll, J. Wisdom, R. West, G. Neukum, T. Denk, R. Wagner, T. Roatsch, et al. (2006)
Science 311, 1393-1401
   Abstract »    Full Text »    PDF »
Identification of a dynamic atmosphere at Enceladus with the Cassini magnetometer..
M. K. Dougherty, K. K. Khurana, F. M. Neubauer, C. T. Russell, J. Saur, J. S. Leisner, and M. E. Burton (2006)
Science 311, 1406-1409
   Abstract »    Full Text »    PDF »
Enceladus' varying imprint on the magnetosphere of Saturn..
G. H. Jones, E. Roussos, N. Krupp, C. Paranicas, J. Woch, A. Lagg, D. G. Mitchell, S. M. Krimigis, and M. K. Dougherty (2006)
Science 311, 1412-1415
   Abstract »    Full Text »    PDF »
Cassini dust measurements at Enceladus and implications for the origin of the E ring..
F. Spahn, J. Schmidt, N. Albers, M. Horning, M. Makuch, M. Seiss, S. Kempf, R. Srama, V. Dikarev, S. Helfert, et al. (2006)
Science 311, 1416-1418
   Abstract »    Full Text »    PDF »
Cassini ion and neutral mass spectrometer: Enceladus plume composition and structure..
J. H. Waite Jr., M. R. Combi, W.-H. Ip, T. E. Cravens, R. L. McNutt Jr., W. Kasprzak, R. Yelle, J. Luhmann, H. Niemann, D. Gell, et al. (2006)
Science 311, 1419-1422
   Abstract »    Full Text »    PDF »
Enceladus' water vapor plume..
C. J. Hansen, L. Esposito, A. I. F. Stewart, J. Colwell, A. Hendrix, W. Pryor, D. Shemansky, and R. West (2006)
Science 311, 1422-1425
   Abstract »    Full Text »    PDF »
Composition and physical properties of Enceladus' surface..
R. H. Brown, R. N. Clark, B. J. Buratti, D. P. Cruikshank, J. W. Barnes, R. M. E. Mastrapa, J. Bauer, S. Newman, T. Momary, K. H. Baines, et al. (2006)
Science 311, 1425-1428
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)