The discovery of inhabited exoplanets hinges on identifying biosignature gases. JWST is revealing potential biosignatures in exoplanet atmospheres, though their presence is yet to provide strong evidence for life.
The central challenge is attribution: how to confidently identify biogenic sources while ruling out, or deeming unlikely, abiotic explanations? Attribution is particularly difficult for individual planets, especially regarding system-scale stochastic processes that could set atmospheric conditions.
To address this, we here propose a comparative multi-planet approach: comparing atmospheric compositions across multiple planets within a system to empirically define the ‘abiotic baseline’. This baseline serves as a reference point for biosignatures, and enables marginalisation over inaccessible, shared abiotic parameters.
To read more, click here.