Can Isotopologues Be Used as Biosignature Gases in Exoplanet Atmospheres?

Fuente: arXiv
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Autores principales: Glidden, Ana, Seager, Sara, Petkowski, Janusz J., Ono, Shuhei
Formato: Preprint
Publicado: 2024
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author Glidden, Ana
Seager, Sara
Petkowski, Janusz J.
Ono, Shuhei
author_facet Glidden, Ana
Seager, Sara
Petkowski, Janusz J.
Ono, Shuhei
contents Isotopologue ratios are anticipated to be one of the most promising signs of life that can be observed remotely. On Earth, carbon isotopes have been used for decades as evidence of modern and early metabolic processes. In fact, carbon isotopes may be the oldest evidence for life on Earth, though there are alternative geological processes that can lead to the same magnitude of fractionation. However, using isotopologues as biosignature gases in exoplanet atmospheres presents several challenges. Most significantly, we will only have limited knowledge of the underlying abiotic carbon reservoir of an exoplanet. Atmospheric carbon isotope ratios will thus have to be compared against the local interstellar medium or, better yet, their host star. A further substantial complication is the limited precision of remote atmospheric measurements using spectroscopy. The various metabolic processes which cause isotope fractionation cause less fractionation than anticipated measurement precision (biological fractionation is typically 2 to 7%). While this level of precision is easily reachable in the laboratory or with special in situ instruments, it is out of reach of current telescope technology to measure isotope ratios for terrestrial exoplanet atmospheres. Thus, gas isotopologues are poor biosignatures for exoplanets given our current and foreseeable technological limitations.
format Preprint
id arxiv_https___arxiv_org_abs_2401_15153
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Can Isotopologues Be Used as Biosignature Gases in Exoplanet Atmospheres?
Glidden, Ana
Seager, Sara
Petkowski, Janusz J.
Ono, Shuhei
Earth and Planetary Astrophysics
Isotopologue ratios are anticipated to be one of the most promising signs of life that can be observed remotely. On Earth, carbon isotopes have been used for decades as evidence of modern and early metabolic processes. In fact, carbon isotopes may be the oldest evidence for life on Earth, though there are alternative geological processes that can lead to the same magnitude of fractionation. However, using isotopologues as biosignature gases in exoplanet atmospheres presents several challenges. Most significantly, we will only have limited knowledge of the underlying abiotic carbon reservoir of an exoplanet. Atmospheric carbon isotope ratios will thus have to be compared against the local interstellar medium or, better yet, their host star. A further substantial complication is the limited precision of remote atmospheric measurements using spectroscopy. The various metabolic processes which cause isotope fractionation cause less fractionation than anticipated measurement precision (biological fractionation is typically 2 to 7%). While this level of precision is easily reachable in the laboratory or with special in situ instruments, it is out of reach of current telescope technology to measure isotope ratios for terrestrial exoplanet atmospheres. Thus, gas isotopologues are poor biosignatures for exoplanets given our current and foreseeable technological limitations.
title Can Isotopologues Be Used as Biosignature Gases in Exoplanet Atmospheres?
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2401.15153