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Home > Research > Publications & Outputs > Peak emission altitude of Saturn's H3+ aurora
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Peak emission altitude of Saturn's H3+ aurora

Research output: Contribution to journalJournal article

Published

  • Tom S. Stallard
  • Henrik Melin
  • Steve Miller
  • Sarah V. Badman
  • Robert H. Brown
  • Kevin H. Baines
Article numberL15103
Journal publication date7/08/2012
JournalGeophysical Research Letters
Journal number15
Volume39
Number of pages5
Original languageEnglish

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.

Bibliographic note

©2012. American Geophysical Union. All Rights Reserved.