JWST will soon obtain the first transit spectra of habitable zone Earth-like planets. However, observations will be expensive and time-consuming due to large experimental uncertainties. Moreover, because these planets’ climates are very sensitive to several difficult-to-constrain variables, it will be challenging to infer the specifics of their climates from their spectra. Theoretical modelling, which is far less resource-intensive than observations and can cover a much larger sample of planets, can lay the groundwork for understanding habitable exoplanet climates and interpreting telescope data. In this work, I use a 3D general circulation model to systematically explore a parameter space of potentially habitable exoplanets, focusing on those which will be easiest to observe with JWST. I then use a radiative transfer model to generate synthetic water vapour transit spectra from my climate simulations. In this talk, I will discuss the interdependent effects of land cover, planet size, and atmosphere mass on the climates of these planets and show how vastly different climates can yield similar transit spectra. I will also discuss a transition between climate regimes in simulations with thicker atmospheres. Because a given exoplanet’s land cover and atmosphere mass will likely be unconstrained, these variables may represent a fundamental uncertainty in transit spectrum interpretation.
Host: Christian DiMaria