The CH<SUB>4</SUB> abundance in Jupiter's upper atmosphere

DOI: 
10.1051/0004-6361/202141933
Publication date: 
08/06/2022
Main author: 
Sánchez-López, A.
IAA authors: 
López-Puertas, M.;García-Comas, M.;Funke, B.
Authors: 
Sánchez-López, A.;López-Puertas, M.;García-Comas, M.;Funke, B.;Fouchet, T.;Snellen, I. A. G.
Journal: 
Astronomy and Astrophysics
Publication type: 
Article
Volume: 
662
Pages: 
A91
Abstract: 
Hydrocarbon species, and in particular CH<SUB>4</SUB>, play a key role in the stratosphere-thermosphere boundary of Jupiter, which occurs around the μ-bar pressure level. Previous analyses of solar occultation, He and Ly-α airglow, and ISO/SWS measurements of the radiance around 3.3 μm have inferred significantly different methane concentrations. Here we aim to accurately model the CH<SUB>4</SUB> radiance at 3.3 μm measured by ISO/SWS by using a comprehensive non-local thermodynamic equilibrium model and the most recent collisional rates measured in the laboratory for CH<SUB>4</SUB> to shed new light onto the methane concentration in the upper atmosphere of Jupiter. These emission bands have been shown to present a peak contribution precisely at the μ-bar level, hence directly probing the region of interest. We find that a high CH<SUB>4</SUB> concentration is necessary to explain the data, in contrast with the most recent analyses, and that the observations favour the lower limit of the latest laboratory measurements of the CH<SUB>4</SUB> collisional relaxation rates. Our results provide precise constraints on the composition and dynamics of the lower atmosphere of Jupiter.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2022A&A...662A..91S/abstract
ADS Bibcode: 
2022A&A...662A..91S
Keywords: 
planets and satellites: atmospheres;methods: data analysis - techniques: spectroscopic;planets and satellites: individual: Jupiter;Astrophysics - Earth and Planetary Astrophysics