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Saturn's equinoctial auroras

Research output: Contribution to journalJournal article


  • J. D. Nichols
  • S. V. Badman
  • E. J. Bunce
  • J. T. Clarke
  • S. W. H. Cowley
  • F. J. Crary
  • M. K. Dougherty
  • J.-c. Gérard
  • D. Grodent
  • K. C. Hansen
  • W. S. Kurth
  • D. G. Mitchell
  • W. R. Pryor
  • T. S. Stallard
  • D. L. Talboys
  • S. Wannawichian
Article numberL24102
<mark>Journal publication date</mark>12/2009
<mark>Journal</mark>Geophysical Research Letters
Issue number24
Number of pages5
<mark>Original language</mark>English


We present the first images of Saturn's conjugate equinoctial auroras, obtained in early 2009 using the Hubble Space Telescope. We show that the radius of the northern auroral oval is ∼1.5° smaller than the southern, indicating that Saturn's polar ionospheric magnetic field, measured for the first time in the ionosphere, is ∼17% larger in the north than the south. Despite this, the total emitted UV power is on average ∼17% larger in the north than the south, suggesting that field-aligned currents (FACs) are responsible for the emission. Finally, we show that individual auroral features can exhibit distinct hemispheric asymmetries. These observations will provide important context for Cassini observations as Saturn moves from southern to northern summer.

Bibliographic note

Copyright 2009 by the American Geophysical Union.