Extended Data Fig. 9: Models of varying metallicity (top) and C/O ratio (bottom) compared to the FIREFLy reduction.
From: Early Release Science of the exoplanet WASP-39b with JWST NIRSpec PRISM
A comparison of cloud-free PICASO 3.0 RCTE models across a span of metallicities with the best-fit C/O ratio (0.68) is shown in the top panel. Each line coloured from faded to deep pink represents models with different metallicities between sub-solar to super-solar values. The simultaneous lack of a prominent CH4 feature at 2.3 and 3.3 µm and the presence of a strong CO2 feature indicate that the observations disfavor a low-metallicity atmosphere. The bottom panel shows transmission spectrum models with different C/O ratios from sub-solar to super-solar values at 10×solar metallicity compared with the observed spectrum. The cloudy best-fit model obtained with the grid retrieval framework also has been shown in both the panels with the grey line. As before, the errorbars are 1σ standard deviations.
