The H3+ ionosphere of Uranus: decades-long cooling and local-time morphology.pdf (1.17 MB)
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The H3+ ionosphere of Uranus: decades-long cooling and local-time morphology.

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journal contribution
posted on 10.09.2019, 08:33 by H Melin, LN Fletcher, TS Stallard, S Miller, LM Trafton, L Moore, J O'Donoghue, RJ Vervack, N Dello Russo, L Lamy, C Tao, MN Chowdhury
The upper atmosphere of Uranus has been observed to be slowly cooling between 1993 and 2011. New analysis of near-infrared observations of emission from H3+ obtained between 2012 and 2018 reveals that this cooling trend has continued, showing that the upper atmosphere has cooled for 27 years, longer than the length of a nominal season of 21 years. The new observations have offered greater spatial resolution and higher sensitivity than previous ones, enabling the characterization of the H3+ intensity as a function of local time. These profiles peak between 13 and 15 h local time, later than models suggest. The NASA Infrared Telescope Facility iSHELL instrument also provides the detection of a bright H3+ signal on 16 October 2016, rotating into view from the dawn sector. This feature is consistent with an auroral signal, but is the only of its kind present in this comprehensive dataset. This article is part of a discussion meeting issue 'Advances in hydrogen molecular ions: H3+, H5+ and beyond'.

Funding

H.M. was supported by the STFC grant no. ST/N000749/1. L.L. was supported by CNES and CNRS/INSU programs of planetology and heliophysics.

History

Citation

Philosophical Transactions A: Mathematical, Physical and Engineering Sciences, 2019, A 377: 20180408.

Author affiliation

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

Version

VoR (Version of Record)

Published in

Philosophical Transactions A: Mathematical

Publisher

Royal Society, The

eissn

1471-2962

Acceptance date

07/04/2019

Copyright date

2019

Available date

10/09/2019

Publisher version

https://royalsocietypublishing.org/doi/10.1098/rsta.2018.0408

Notes

The data are available in public telescope archives, or from H.M. upon request.

Language

en

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