Morphological differences between Saturn's ultraviolet aurorae and those of Earth and Jupiter

J. T Clarke; J.-C Gerard; E. J Bunce; T Hill; J Kim; D Grodent; S Wannawichian; J Gostin; J Connerney; F Crary; M Dougherty; W Kurth; S. W. H Cowley

doi:10.1038/nature03331

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Morphological differences between Saturn's ultraviolet aurorae and those of Earth and Jupiter

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Morphological differences between Saturn's ultraviolet aurorae and those of Earth and Jupiter

J. T Clarke, J.-C Gerard, E. J Bunce, T Hill, J Kim, D Grodent, S Wannawichian, J Gostin, J Connerney, F Crary, …

Nature (London), Vol.433(7027), pp.717-719

02/17/2005

DOI: 10.1038/nature03331

PMID: 15716945

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Abstract

It has often been stated that Saturn's magnetosphere and aurorae are intermediate between those of Earth, where the dominant processes are solar wind driven1, and those of Jupiter, where processes are driven by a large source of internal plasma2,3,4. But this view is based on information about Saturn that is far inferior to what is now available. Here we report ultraviolet images of Saturn, which, when combined with simultaneous Cassini measurements of the solar wind5 and Saturn kilometric radio emission6, demonstrate that its aurorae differ morphologically from those of both Earth and Jupiter. Saturn's auroral emissions vary slowly; some features appear in partial corotation whereas others are fixed to the solar wind direction; the auroral oval shifts quickly in latitude; and the aurora is often not centred on the magnetic pole nor closed on itself. In response to a large increase in solar wind dynamic pressure5 Saturn's aurora brightened dramatically, the brightest auroral emissions moved to higher latitudes, and the dawn side polar regions were filled with intense emissions. The brightening is reminiscent of terrestrial aurorae, but the other two variations are not. Rather than being intermediate between the Earth and Jupiter, Saturn's auroral emissions behave fundamentally differently from those at the other planets.

Astronomy

Earth, ocean, space

Exact sciences and technology

Ionospheres; magnetospheres

Jupiter

Planetary, asteroid, and satellite characteristics and properties

Planets, their satellites and rings. Asteroids

Saturn

Solar system

Details

Title: Subtitle: Morphological differences between Saturn's ultraviolet aurorae and those of Earth and Jupiter
Creators: J. T Clarke - Boston University
J.-C Gerard - University of Liège
E. J Bunce - University of Leicester
T Hill - Rice University
J Kim - Yonsei University
D Grodent - University of Liège
S Wannawichian - Boston University
J Gostin - Université de Liège, Alice du 6 Aout - Sart Tilman, 4000 Liège, Belgium
J Connerney - Goddard Space Flight Center
F Crary - Southwest Research Institute
M Dougherty - Imperial College London
W Kurth - University of Iowa
S. W. H Cowley - University of Leicester
Resource Type: Journal article
Publication Details: Nature (London), Vol.433(7027), pp.717-719
DOI: 10.1038/nature03331
PMID: 15716945
NLM abbreviation: Nature
ISSN: 0028-0836
eISSN: 1476-4687
Publisher: Nature Publishing
Language: English
Date published: 02/17/2005
Academic Unit: Physics and Astronomy
Record Identifier: 9984455657202771

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