Geoscience and the Search for Life Beyond the Solar System

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Extrasolar Planet

How can scientists conclude with high confidence that an exoplanet hosts life? As telescopes come on line over the next 20 years that can directly observe photons from terrestrial exoplanets, this question will dictate the activities of many scientists across many fields.

The expected data will be sparse and with low signal-to-noise, which will make disentangling biosignatures from abiotic features challenging. Our Earth is not just unique in that it hosts life, it is also the only terrestrial planet with direct observations of its interior through seismic waves, and compositional evolution through field and laboratory measurements. This extensive research reveals a planet born from collisions between worlds, followed by a complicated biogeochemical evolution.

Exoplanet interiors, on the other hand, can only be constrained by the following observations: 1) photometric and spectroscopic analysis of the planet's atmosphere, 2) spectroscopic and photometric analysis of the host star, and 3) companion planet properties. From these (future) data, astrobiologists must generate plausible compositional and evolutionary models that constrain a potentially habitable exoplanet's internal properties and history, provide environmental context, and rule out geochemical explanations for any putative biosignatures.

The goal of this white paper is to frame the role of geophysical and geochemical processes relevant to the search for life beyond the Solar System and to identify critical, but understudied, areas of future research.

Rory Barnes, Anat Shahar, Cayman Unterborn, Hilairy Hartnett, Ariel Anbar, Brad Foley, Peter Driscoll, S.-H. Dan Shim, Thomas Quinn, Kayla Iacovino, Stephen Kane, Steven Desch, Norman Sleep, David Catling
(Submitted on 26 Jan 2018)

Comments: 6 pages, 1 figure. White paper submitted to the NAS Astrobiology Science Strategy solicitation
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:1801.08970 [astro-ph.EP] (or arXiv:1801.08970v1 [astro-ph.EP] for this version)
Submission history
From: Rory Barnes
[v1] Fri, 26 Jan 2018 20:55:30 GMT (294kb)
https://arxiv.org/abs/1801.08970
Astrobiology

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