Saturn’s northern auroras as observed using the Hubble Space Telescope

Nichols, J.D. and Badman, S.V. and Bunce, E.J. and Clarke, J.T. and Cowley, S.W.H. and Hunt, G.J. and Provan, G. (2016) Saturn’s northern auroras as observed using the Hubble Space Telescope. Icarus, 263 (1). pp. 17-31. ISSN 0019-1035

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Abstract

We discuss the features of Saturn’s northern FUV auroras as observed during a program of Hubble Space Telescope observations which executed over 2011-2013 and culminated, along with Cassini observations, in a comprehensive multi-spectral observing campaign. Our 2011-2013 observations of the northern aurora are also compared with those from our 2007-2008 observation of the southern aurora. We show that the variety of morphologies of the northern auroras is broadly consistent with the southern, and determine the statistical equatorward and poleward boundary locations. We find that our boundaries are overall consistent with previous observations, although a modest poleward displacement of the poleward boundaries is due to the increased prevalence of poleward auroral patches in the noon and afternoon sectors during this program, likely due to the solar wind interaction. We also show that the northern auroral oval oscillates with the northern planetary period oscillation (PPO) phase in an elongated ellipse with semi-major axis ∼1.6°1.6° oriented along the post-dawn/post-dusk direction. We further show that the northern auroras exhibit dawn-side brightenings at zero northern magnetic PPO phase, although there is mixed evidence of auroral emissions fixed in the rotating frame of the northern PPO current system, such that overall the dependence of the auroras on northern magnetic phase is somewhat weak.

Item Type: Journal Article
Journal or Publication Title: Icarus
Additional Information: This is the author’s version of a work that was accepted for publication in Icarus. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Icarus, 263, 2016 DOI: 10.1016/j.icarus.2015.09.008
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/1900/1912
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 75817
Deposited By: ep_importer_pure
Deposited On: 30 Oct 2015 09:52
Refereed?: Yes
Published?: Published
Last Modified: 17 Oct 2019 00:37
URI: https://eprints.lancs.ac.uk/id/eprint/75817

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