Detectability of Atmospheric Biosignatures in Earth Analogs with Varying Surface Boundary Conditions: Prospects for Characterization in the UV, Visible, Near-Infrared, and Mid-Infrared Regions

The search for potentially habitable exoplanets centers on detecting biosignature molecules in Earth-like atmospheres, which makes it essential to understand their detectability under biologically and geologically influenced conditions.

In this study, we model the reflection and thermal emission spectra of such atmospheres across the UV/VIS/NIR and mid-IR regions and simulate their detectability with future mission concepts such as the Habitable Worlds Observatory (HWO) and the Large Interferometer for Exoplanets (LIFE).

We employ Numerical Weather Prediction (NWP) model data, based on Earth’s atmosphere, to derive temperature pressure profiles and couple them with a 1D photochemical model to assess the detectability of these molecules in Earth analogs located 10 parsecs away. We investigate the dominant reaction pathways and their contributions to the atmospheric composition of an Earth analog, with a focus on how they shape the resulting molecular signatures.

We also examine the role of surface boundary conditions, which indirectly trace the effects of biological and geological processes, on the detectability of these molecules using HWO- and LIFE-type mission concepts. Our findings indicate that O₃ is detectable with both mission concepts, while H₂O requires specific surface humidity levels for detection with LIFE and shows only potential detectability with HWO. CO₂ is detectable with LIFE.

Both N₂O and CH₄ require continuous surface outgassing for potential detection with LIFE, and CH₄ further requires low surface humidity to prevent masking by water features. Our work highlights the feasibility of characterizing the atmospheres of Earth analogs in the UV/VIS/NIR and mid-IR domains using HWO- and LIFE-type mission concepts and offers guidance for the development of future missions operating in these spectral regions.

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 (or arXiv:2512.10277v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2512.10277
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Submission history
From: Liton Majumdar
[v1] Thu, 11 Dec 2025 04:34:49 UTC (7,373 KB)
https://arxiv.org/abs/2512.10277
Astrobiology,