As Enceladus orbits rapidly around Saturn with a period of only 1.37 Earth days, the ejected water vapor is spread along and around its orbit, forming a large torus around the gas giant.
Enceladus is the sixth-largest moon of Saturn with a diameter of 505 km (314 miles).
Discovered in 1789 by the German-born British astronomer William Herschel, this moon is one of the most exciting scientific targets in our Solar System in the search for life beyond Earth.
Enceladus is likely the largest source of water within the Saturnian system, with water and other materials jetted into Saturn orbit by localized geological activity.
Early hints of geological activity on Enceladus were provided by NASA’s Voyager and telescopic observations in the 1980s and 1990s, finding a close association between Enceladus’ orbit and Saturn’s outermost and widest ring — the dense E-ring.
In 2005, multiple instruments onboard NASA’s Cassini spacecraft discovered a plume of gases and ice grains emerging from fissures in the south polar region of Enceladus.
A torus of water along Enceladus’ orbit was recently observed via sub-millimeter spectroscopy with ESA’s Herschel Observatory.
The Cassini measurements of the plume gas were made using mass spectrometry along specific flyby trajectories and via stellar occultation in the inner region of the plume (less than 200 km).
In contrast, the measurements of the torus were not spatially resolved, but they indicated the presence of water vapor widely throughout the Saturnian system.
While the plume’s flux of icy grains varies on multiple timescales, the variations in the vapor flux are much less well understood, together with how these affect the structure and evolution of the torus.
By analyzing the molecular emissions across large distances from Enceladus with the NASA/ESA/CSA James Webb Space Telescope, Dr. Geronimo Villanueva from NASA’s Goddard Space Flight Center and colleagues were able to map the distribution of outgassed…
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