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Sulfur chemistry in the atmospheres of warm and hot Jupiters

Published version
Peer-reviewed

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Authors

Hobbs, R 
Rimmer, PB 
Madhusudhan, N 

Abstract

We present and validate a new network of atmospheric thermo-chemical and photo-chemical sulfur reactions. We use a 1-D chemical kinetics model to investigate these reactions as part of a broader HCNO chemical network in a series of hot and warm Jupiters. We find that temperatures approaching 1400K are favourable for the production of H2S and HS around 10−3bar, the atmospheric level where detection by transit spectroscopy may be possible, leading to mixing ratios of around 10−6. At lower temperatures, down to 1000K, the abundance of S2 can be up to a mixing ratio of 10−5 at the same pressure, at the expense of H2S and HS, which are depleted down to a mixing ratio of 10−6. We also investigate how the inclusion of sulfur can manifest in an atmosphere indirectly, by its effect on the abundance of non-sulfur-bearing species. We find that in a model of the atmosphere of HD 209458 b, the inclusion of sulfur can lower the abundance of NH3, CH4 and HCN by up to two orders of magnitude around 10−3bar. In the atmosphere of the warm Jupiter 51 Eri b, we additionally find the inclusion of sulphur depletes the peak abundance of CO2 by a factor of five, qualitatively consistent with prior models. We note that many of the reactions used in the network have poorly determined rates, especially at higher temperatures. To obtain a truly accurate idea of the impact of sulfur chemistry in hot and warm Jupiter atmospheres, new measurements of these reaction rates must take place.

Description

Keywords

planets and satellites: atmospheres, planets and satellites: composition, planets and satellites: gaseous planets, planets and satellites: individual: HD 209458 b, planets and satellites: individual: 51 Eri b

Journal Title

Monthly Notices of the Royal Astronomical Society

Conference Name

Journal ISSN

0035-8711
1365-2966

Volume Title

506

Publisher

Oxford University Press (OUP)

Rights

All rights reserved