New images of Saturn obtained by a University ofColorado at Boulder-led team on June 21 using an instrument on theCassini spacecraft show auroral emissions at its poles similar toEarth's Northern Lights.
Taken with the Ultraviolet Imaging Spectrograph aboard theCassini orbiter, the two UV images, invisible to the human eye, are thefirst from th e Cassini-Huygens mission to capture the entire "oval" ofthe auroral emissions at Saturn's south pole. They also show similaremissions at Saturn's north pole, according to CU-Boulder ProfessorLarry Esposito, principal investigator of the UVIS instrument built atCU-Boulder's Laboratory for Atmospheric and Space Physics, andProfessor Wayne Pryor of Central Arizona College, a UVIS team memberand former CU graduate student.
In the false-color images, blue represents aurora emissionsfrom hydrogen gas excited by electron bombardment, while red-orangerepresents reflected sunlight. The images show that the aurora lightsat the polar regions respond rapidly to changes in the solar wind, saidthe researchers. Previous images have been taken closer to the equator,making it difficult to see the polar regions.
Major changes in the emissions inside the Saturn south-poleaurora are evident by comparing the two images, which were taken aboutone hour apart, they said. The brightest spot in the left aurora fades,and a bright spot appears in the middle of the aurora in the secondimage.
Made by slowly scanning the UVIS instrument across the planet,the images also contain more than 2,000 wavelengths of spectralinformation within each picture element. Researchers will use thewavelength information to study Saturn's auroras, gases, and hazes andtheir changing distributions.
The UVIS observation team includes researchers fromCU-Boulder, NASA's Jet Propulsion Laboratory, Central Arizona Collegeand the University of Southern California.
The Cassini-Huygens mission is a cooperative project of NASA,the European Space Agency and the Italian Space Agency. The JetPropulsion Laboratory, a division of the California Institute ofTechnology in Pasadena, manages the Cassini- Huygens mission for NASA'sSpace Science Mission Directorate in Washington, D.C.
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