Editor's Summary

13 November 2008

Planetary aurora: Cassini's new angle on Saturn

Planetary aurorae are generally produced by currents flowing between the planet's ionosphere and magnetosphere, which accelerate energetic charged particles that then hit the upper atmosphere. Recent models of Saturn's aurora predict only weak emission away from the main auroral oval. Stallard et al. now present Cassini infrared images taken from a novel angle, providing the first nightside auroral view. They reveal emissions both poleward and equatorward of the main oval. The polar emissions vary with time, and seem not to be linked with strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained by current models of Saturn's magnetosphere.

Letter: Complex structure within Saturn's infrared aurora

Tom Stallard, Steve Miller, Makenzie Lystrup, Nicholas Achilleos, Emma J. Bunce, Christopher S. Arridge, Michele K. Dougherty, Stan W. H. Cowley, Sarah V. Badman, Dean L. Talboys, Robert H. Brown, Kevin H. Baines, Bonnie J. Buratti, Roger N. Clark, Christophe Sotin, Phil D. Nicholson & Pierre Drossart

doi:10.1038/nature07440

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