surface pressure Archives

Hycean and mini-Neptune scenarios with two photochemical models. Top row: Original simulations from Wogan et al. (2024), showing the mixing ratio of molecules against atmospheric pressure in bar. Bottom row: VULCAN simulations of the same scenarios with equivalent assumptions (see main text). The scenarios are: an uninhabited Hycean (left column), an inhabited Hycean (middle column), and a mini-Neptune case (right column). The given molecular constraints are from the “One offset” case (Madhusudhan et al. 2023b) as this case gives the best fit to the observed data. 1-σ error bars are given for detected molecules (CH4 - orange; CO2 - green), and 2-σ upper limits are given for CO (purple), H2O (blue), and NH3 (grey), which were not detected by Madhusudhan et al. (2023b). The photosphere, the region in the atmosphere which impacts the transmission spectrum observed, is given in a light grey shade between 10−2 – 10−4 bar. A variety of simulations were run with both the W24 setup (see Table A1) and VULCAN (see Table A2). All of the simulations shown in this figure use the GJ 176 spectrum. Only the inhabited Hycean scenarios in both models are consistent with the retrieved abundances. -- astro-ph.EP

Considerations for Photochemical Modeling of Possible Hycean Worlds

by Keith CowingOctober 11, 2024September 18, 2025

JWST is revolutionising the study of temperate sub-Neptunes, starting with the first detection of carbon-bearing molecules in the habitable-zone sub-Neptune K2-18 b. The retrieved abundances of CH4 and CO2 and […]

surface pressure

Considerations for Photochemical Modeling of Possible Hycean Worlds

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