Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets

Fuente: arXiv
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Main Authors: Triaud, Amaury H. M. J., de Wit, Julien, Klein, Frieder, Turbet, Martin, Rackham, Benjamin V., Niraula, Prajwal, Glidden, Ana, Jagoutz, Oliver E., Pec, Matej, Petkowski, Janusz J., Seager, Sara, Selsis, Franck
Format: Preprint
Published: 2023
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author Triaud, Amaury H. M. J.
de Wit, Julien
Klein, Frieder
Turbet, Martin
Rackham, Benjamin V.
Niraula, Prajwal
Glidden, Ana
Jagoutz, Oliver E.
Pec, Matej
Petkowski, Janusz J.
Seager, Sara
Selsis, Franck
author_facet Triaud, Amaury H. M. J.
de Wit, Julien
Klein, Frieder
Turbet, Martin
Rackham, Benjamin V.
Niraula, Prajwal
Glidden, Ana
Jagoutz, Oliver E.
Pec, Matej
Petkowski, Janusz J.
Seager, Sara
Selsis, Franck
contents The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O$_2$, will be challenging to detect with present or upcoming observatories. Here we suggest a new signature. A low carbon abundance in the atmosphere of a temperate rocky planet, relative to other planets of the same system, traces the presence of substantial amount of liquid water, plate tectonic and/or biomass. We show that JWST can already perform such a search in some selected systems like TRAPPIST-1 via the CO$_2$ band at $4.3\,\rm μm$, which falls in a spectral sweet spot where the overall noise budget and the effect of cloud/hazes are optimal. We propose a 3-step strategy for transiting exoplanets: 1) detection of an atmosphere around temperate terrestrial planets in $\sim 10$ transits for the most favorable systems, (2) assessment of atmospheric carbon depletion in $\sim 40$ transits, (3) measurements of O$_3$ abundance to disentangle between a water- vs biomass-supported carbon depletion in $\sim100$ transits. The concept of carbon depletion as a signature for habitability is also applicable for next-generation direct imaging telescopes.
format Preprint
id arxiv_https___arxiv_org_abs_2310_14987
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets
Triaud, Amaury H. M. J.
de Wit, Julien
Klein, Frieder
Turbet, Martin
Rackham, Benjamin V.
Niraula, Prajwal
Glidden, Ana
Jagoutz, Oliver E.
Pec, Matej
Petkowski, Janusz J.
Seager, Sara
Selsis, Franck
Earth and Planetary Astrophysics
The conventional observables to identify a habitable or inhabited environment in exoplanets, such as an ocean glint or abundant atmospheric O$_2$, will be challenging to detect with present or upcoming observatories. Here we suggest a new signature. A low carbon abundance in the atmosphere of a temperate rocky planet, relative to other planets of the same system, traces the presence of substantial amount of liquid water, plate tectonic and/or biomass. We show that JWST can already perform such a search in some selected systems like TRAPPIST-1 via the CO$_2$ band at $4.3\,\rm μm$, which falls in a spectral sweet spot where the overall noise budget and the effect of cloud/hazes are optimal. We propose a 3-step strategy for transiting exoplanets: 1) detection of an atmosphere around temperate terrestrial planets in $\sim 10$ transits for the most favorable systems, (2) assessment of atmospheric carbon depletion in $\sim 40$ transits, (3) measurements of O$_3$ abundance to disentangle between a water- vs biomass-supported carbon depletion in $\sim100$ transits. The concept of carbon depletion as a signature for habitability is also applicable for next-generation direct imaging telescopes.
title Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2310.14987