Searching For Life-As-We-Don’t-Know-It: Mission-relevant Application of Assembly Theory For Exoplanet Life Detection

This white paper introduces a framework for applying Assembly Theory (AT) to planetary atmospheres as a biosignature framework suitable for the Habitable Worlds Observatory (HWO).

AT quantifies the minimum combinatorial complexity required to co-construct an observed ensemble of molecular species, providing a measure of how much selection and evolution is encoded in a planetary atmosphere’s chemical space, without assuming any specific biochemistry, kinetics nor metabolism.

We outline some forthcoming results applying this framework and how it can be extended to population-level exoplanet studies, validated against existing spectroscopic data, and used to directly inform HWO instrumental requirements.

Rather than imposing a binary alive/dead classification, AT-based atmospheric analysis would provide a continuous measure of planetary complexity, opening a path toward detecting life-as-we-don’t-know-it.

Sara Walker, Estelle Janin, Evgenya Shkolnik, Louie Slocombe

Comments: Habitable Worlds Observatory RFI
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2603.11086 [astro-ph.IM](or arXiv:2603.11086v1 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2603.11086
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Submission history
From: Sara Walker
[v1] Wed, 11 Mar 2026 04:26:47 UTC (237 KB)
https://arxiv.org/abs/2603.11086
Astrobiology,