A laboratory-to-model approach to understanding exoplanet biosignatures
Abstract
The assessment of exoplanet habitability is predominantly based on the measurement of biosignature gases, usually in the form of triplicate sets of CH4, O2, CO2, and O3, among other molecules indicative of life. Because exoplanets are distant, this is predicated on the ability to characterize atmospheres that would contain these gases at detectable limits for remote telescopes. However, this methodology often lacks a mechanism relating atmospheric detections to the potentially biogenic sources that emit these gases at the planetary surface. This can lead to misinterpretations between abiotic signatures and truly biotic sources. Here we present a study to quantitatively link surface processes and atmospheric chemistry for potentially habitable exoplanets using actual microbiological experiments. We will measure gas outputs from actual field samples of microbial communities that are from various ecosystems in which a multitude of major biogenic gases can be quantified. These measurements will serve as exoplanet surface inputs to the Atmsopheric-Rock-Ocean-Chemistry (AROC) model, which couples an aqueous geochemistry code and KINETICS (a photochemistry code) to trace surface-to-atmosphere chemistry. In this way, we can to bridge the gap between exoplanet biosignatures and the very biology and metabolisms found in nature. The results from this study can help guide the design of future ground- and space-based telescopes (e.g., JWST, ARIEL, ELTs, HabEx, LUVOIR, Origins) by identifying additional biosignatures that would help distinguish between atmospheric conditions that may or may not be conducive to life.
- Publication:
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AAS/Division for Extreme Solar Systems Abstracts
- Pub Date:
- August 2019
- Bibcode:
- 2019ESS.....433108K