Enceladus jet sources
Sat Oct 13, 2007 at 10:32 UTC
Cassini imaging scientists used the Cassini spacecraft camera to help them identify the source locations for individual jets spurting ice particles, water vapor and trace organic compounds from the surface of Saturn's moon Enceladus.
Their study -- published in the Oct. 11, 2007, issue of the journal Nature -- identifies eight source locations, all on the prominent tiger stripe fractures, or sulci, in the moon's south polar region. Some of the sources occur in regions not yet observed by Cassini's composite infrared spectrometer, and the researchers predict that future Cassini observations of those locations will find elevated temperatures.
To identify jet source locations on the surface, imaging scientists carefully measured the locations and orientations of individual jets observed along the moon's limb in Cassini images taken from multiple viewing angles. For each jet measurement, the researchers then computed a curve, or ground track, on the surface of Enceladus along which that jet might lie. The ground tracks from all of the measurements made in the various images produced many intersections on this map. By considering the jet directions at every possible intersection, the researchers isolated eight clusters of ground track intersections as jet sources.
Image Credit: NASA/JPL/Space Science Institute
High resolution image
This map of the south polar region of Saturn's moon Enceladus shows the correlation between jet sources identified in Cassini imaging data and hot spots on the surface located by the composite infrared spectrometer instrument.
The eight identified jet source locations are labeled with yellow roman numerals. Composite infrared spectrometer hot spots are red boxes labeled with green capital letters. The line-of-sight intersections indicating the measurements of each source in individual images are shown as colored diamonds. White circles indicate the uncertainty in the locations of those sets of intersections.
The map is a polar stereographic projection of Cassini imaging data. The four tiger stripe fractures, or sulci, are labeled here. The south pole is dead center on the map. Key longitudes are also labeled around the perimeter of the map.
Image Credit: NASA/JPL/Space Science Institute
High resolution image
This false-color view was created by combining three clear filter images taken at nearly the same time as PIA07759. This image product was then specially processed to enhance the individual jets that compose the plume. Some artifacts due to the processing are present in the image. The final product was colored as blue for dramatic effect.
The images were acquired with the Cassini spacecraft narrow-angle camera on Nov. 27, 2005 at a distance of approximately 148,000 kilometers (92,000 miles) from Enceladus and at a sun-Enceladus-spacecraft, or phase, angle of 161 degrees. Scale in the original images is about 880 meters (0.5 mile) per pixel. This view has been magnified by a factor of two from the original images.
| Source: Jet Propulsion Laboratory | |
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