A bold reality check: detecting biosignature molecules in Earth-like atmospheres is the key to identifying potentially habitable exoplanets, but the success of this effort hinges on how these signals endure under diverse biological and geological conditions.
This work explores how reflected light and thermal emission from Earth-analog atmospheres would appear across the UV, visible, near-infrared, and mid-infrared bands, and it assesses how detectable these features might be with future missions such as the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE).
Using a Numerical Weather Prediction (NWP) framework grounded in Earth's atmospheric structure, we derive temperature–pressure profiles and couple them to a one-dimensional photochemical model. This setup lets us forecast which biosignature molecules would stand out in Earth-like atmospheres orbiting a star at a distance of 10 parsecs, and to analyze the principal chemical pathways that shape atmospheric composition and the resulting spectral fingerprints.
A central focus is how surface boundary conditions—proxy indicators of biological and geological activity—alter detectability for HWO- and LIFE-like missions. Our results show that ozone (O3) is detectable by both mission concepts. Water vapor (H2O) detection depends on particular surface humidity levels for LIFE, and is only potentially detectable with HWO in some scenarios. Carbon dioxide (CO2) appears detectable with LIFE.
For nitrogen oxides (N2O) and methane (CH4), continuous surface outgassing is necessary for potential detection with LIFE; CH4 detection also requires low surface humidity to avoid being masked by water features. Overall, the study demonstrates the feasibility of characterizing Earth-analog atmospheres in the UV/VIS/NIR and mid-IR using HWO- and LIFE-type platforms and provides practical guidance for shaping future missions that operate in these spectral regions.
Authors: Dibya Bharati Pradhan, Priyankush Ghosh, Oommen P. Jose, Liton Majumdar
Comments: Accepted for publication in The Astrophysical Journal; 28 pages, 8 figures, and 8 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2512.10277 [astro-ph.EP] | https://doi.org/10.48550/arXiv.2512.10277
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