Peak emission altitude of Saturn's H3+ aurora

Stallard, Tom S. and Melin, Henrik and Miller, Steve and Badman, Sarah V. and Brown, Robert H. and Baines, Kevin H. (2012) Peak emission altitude of Saturn's H3+ aurora. Geophysical Research Letters, 39 (15). ISSN 0094-8276

[img]
Preview
PDF (grl29398)
grl29398.pdf - Published Version

Download (349kB)

Abstract

Here we present the first detailed measurement of the altitudinal profile of H3+ emission within Saturn's ionosphere, made using images taken by the VIMS instrument on Cassini on 11–12 October 2006, during a chance alignment between the visible limb of the planet and the position of the main auroral emission. Using this, we show that the emission profile of H3+ can be fitted to a reasonable accuracy with a Gaussian, producing a calculated peak emission altitude at 1155 (±25) km that differs significantly from previous observations of the UV emission profile, and also from the predictions of models that calculated the H3+ emission profile, which suggested that there would be extended emission above the peak emission altitude. This lack of extended emission is most simply explained by differences in the scale height of H and H2, suggesting that models overestimate H2 at high altitudes, with little H2 from 2000 km above the 1 bar level.

Item Type:
Journal Article
Journal or Publication Title:
Geophysical Research Letters
Additional Information:
©2012. American Geophysical Union. All Rights Reserved.
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1900
Subjects:
ID Code:
67079
Deposited By:
Deposited On:
10 Oct 2013 10:42
Refereed?:
Yes
Published?:
Published
Last Modified:
05 Jul 2020 03:48