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Title: Conjugate observations of Saturn’s northern and southern H[superscript + subscript 3] aurorae
Authors: O’Donoghue, James
Stallard, Tom S.
Melin, Henrik
Cowley, Stanley W. H.
Badman, Sarah V.
Moore, Luke
Miller, Steve
Tao, Chihiro
Baines, Kevin H.
Blake, James S.D.
First Published: 20-Nov-2013
Publisher: Elsevier on behalf of Academic Press
Citation: Icarus, 2014, 229, pp. 214-220
Abstract: We present an analysis of recent high spatial and spectral resolution ground-based infrared observations of H[superscript + subscript 3] obtained with the 10-m Keck II telescope in April 2011. We observed H[superscript + subscript 3] emission from Saturn’s northern and southern auroral regions, simultaneously, over the course of more than 2 h, obtaining spectral images along the central meridian as Saturn rotated. Previous ground-based work has derived only an average temperature of an individual polar region, summing an entire night of observations. Here we analyse 20 H[superscript + subscript 3] spectra, 10 for each hemisphere, providing H[superscript + subscript 3] temperature, column density and total emission in both the northern and southern polar regions simultaneously, improving on past results in temporal cadence and simultaneity. We find that: (1) the average thermospheric temperatures are 527 ± 18 K in northern Spring and 583 ± 13 K in southern Autumn, respectively; (2) this asymmetry in temperature is likely to be the result of an inversely proportional relationship between the total thermospheric heating rate (Joule heating and ion drag) and magnetic field strength – i.e. the larger northern field strength leads to reduced total heating rate and a reduced temperature, irrespective of season, and (3) this implies that thermospheric heating and temperatures are relatively insensitive to seasonal effects.
DOI Link: 10.1016/j.icarus.2013.11.009
ISSN: 0019-1035
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2013 The Authors. Published by Elsevier Inc. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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