Prebiosignatures with the Habitable Worlds Observatory (HWO)

TL;DR

The paper proposes using the Habitable Worlds Observatory to detect prebiosignature gases, which can test theories of life's origins on planets that are habitable but uninhabited, emphasizing the importance of UV observations.

Contribution

It introduces the novel concept of prebiosignatures for testing abiogenesis theories with HWO and catalogs testable prebiotic environment theories, highlighting the need for UV capabilities.

Findings

Identification of 5 testable prebiotic environment theories

Ranking of theories by detection plausibility

Emphasis on the necessity of UV (NUV) wavelength coverage

Abstract

The Habitable Worlds Observatory (HWO) aims to characterize habitable exoplanets in search of signs of life. However, detectable life may be rare, either because abiogenesis is intrinsically contingent and unlikely, or because biospheres may efficiently recycle their products. Here, we explore the potential of HWO to test theories of life in the universe even if detectable life is rare by searching for "prebiosignature gases". Prebiosignatures gases are gases whose detection constrains theories of the evolution of prebiotic (habitable but uninhabited) planets, thereby testing theories of abiogenesis and guiding laboratory investigations of the origin of life. We catalog 5 theories of prebiotic environments that are potentially testable by HWO, identify their observational tests, and rank them by perceived detection plausibility. The prebiosignature paradigm is novel and potentially compelling, but considerable work is required to mature it and assess its practical relevance for HWO, especially simulated spectral observation and retrieval studies. However, consideration of the absorption properties of prebiosignature observables alone reveals that coverage at NUV wavelengths (200-400 nm) will be required to effectively realize a prebiosignature science case for HWO, supporting the argument for UV capabilities for HWO.