Posters
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The evolving ozone layer on Earth and exoplanets
Exoplanets 6 presentation poster — Akhil Kumar (first author), GJ Cooke (supervisor)
This poster compares 1D and 3D atmospheric models for ozone production across Earth's oxygenated history and for exoplanets such as Proxima Centauri b. It highlights how model dimensionality affects predictions relevant to future observatories including LIFE and HWO. A manuscript describing this work is in preparation; Akhil Kumar is the first author and I supervised the project.
Ecological modelling of habitable ocean worlds
Rocky Worlds IV, 2026
This poster presents the first application of Lotka–Volterra equations to microbial ecology on habitable hycean exoplanets, modelling anoxic bacterial communities in a vertical water column inspired by worlds such as K2-18 b. We find that a wide range of ecological diversity is possible, with surface phototrophs out-competing deeper species, bacteriophages able to trigger ecosystem collapse, and tidally locked oceans potentially supporting more stable but less dense populations. The paper is published in MNRAS.
Hydrocarbons in the Sub-Neptune regime
Exoclimes VII, 2025
This poster is based on ongoing work.
Is K2-18 b a mini-Neptune or a Hycean World?
Origins Conference, 2024
This poster uses independent photochemical modeling to assess whether JWST's detections of CH4 and CO2 in the habitable-zone sub-Neptune K2-18 b are better explained by a Hycean world or a mini-Neptune scenario. We find that the mini-Neptune interpretation is incompatible with most of the retrieved abundances, while inhabited and uninhabited Hycean scenarios provide better agreement, highlighting how model assumptions such as stellar UV, surface pressure, and albedo strongly shape the interpretation of chemical constraints. The paper is published in the Astrophysical Journal.
Oxygen's control on hydrogen escape in Earth-like atmospheres across GKM dwarf stars
Exoplanets V
This poster is based on ongoing work.
3D simulations of TRAPPIST-1e
Exoclimes VI
This poster is based on the work that was eventually published in the Astrophysical Journal. A special thanks to Stephanie Zeller for designing the poster.
Oxygen as a control on 2.4 billion years of Earth's atmosphere
EAS Leiden, 2021