Saturn's northern auroras as observed using the Hubble Space Telescope
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Published version
Author(s)
Type
Journal Article
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° 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.
Date Issued
2016-01-01
Date Acceptance
2015-09-04
Citation
Icarus, 2016, 263, pp.17-31
ISSN
0019-1035
Publisher
Elsevier
Start Page
17
End Page
31
Journal / Book Title
Icarus
Volume
263
Copyright Statement
© 2015 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://
creativecommons.org/licenses/by/4.0/).
creativecommons.org/licenses/by/4.0/).
License URL
Subjects
Science & Technology
Physical Sciences
Astronomy & Astrophysics
Saturn
Magnetospheres
Aurorae
Hubble Space Telescope observations
INTERPLANETARY MAGNETIC-FIELD
ULTRAVIOLET AURORA
MAGNETOSPHERE
CUSP
Publication Status
Published
Date Publish Online
2015-10-01