Click on the image for movie of
Stellar Data on Plume
New structure, density and composition measurements of Enceladus' water
plume were obtained when the Cassini spacecraft's Ultraviolet Imaging
Spectrograph observed the star zeta Orionis pass behind the plume Oct. 24,
2007, as seen in this animation.
Changes in the starlight as it dimmed while passing through the plume
allowed the spectrograph to identify the plume's physical and chemical
composition. The spectrograph detected four high-density gas streams
composed of water vapor. The density of the water vapor is twice that of
the broad plume of gas that surrounds each jet.
This measurement confirms the theoretical analysis performed prior to the
flyby that showed it was safe for Cassini to fly very closely past
Enceladus, even through part of the plume, during the March 12, 2008
flyby.
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 mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter was designed, developed and assembled at JPL. The
ultraviolet imaging spectrograph was designed and built at, and the team
is based at the University of Colorado, Boulder.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov. The ultraviolet imaging spectrograph team home
page is at http://lasp.colorado.edu/cassini.
