Nichols et al (Published Icarus Jan 2016).pdf (6.21 MB)
Download file

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

Download (6.21 MB)
journal contribution
posted on 11.01.2016, 09:53 by Jonathan D. Nichols, S. V. Badman, E. J. Bunce, J. T. Clarke, Stanley William Herbert Cowley, G. J. Hunt, G. Provan
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.

History

Citation

Icarus, 2016, 263, pp. 17-31 (15)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and Astronomy

Version

VoR (Version of Record)

Published in

Icarus

Publisher

Elsevier for Academic Press Inc.

issn

0019-1035

Acceptance date

04/09/2015

Copyright date

2015

Available date

11/01/2016

Publisher version

http://www.sciencedirect.com/science/article/pii/S001910351500411X

Language

en