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Abiotic O_2 Levels on Planets around F, G, K, and M Stars: Effects of Lightning-produced Catalysts in Eliminating Oxygen False Positives

Harman, C. E. and Felton, R. and Hu, R. and Domagal-Goldman, S. D. and Segura, A. and Tian, F. and Kasting, J. F. (2018) Abiotic O_2 Levels on Planets around F, G, K, and M Stars: Effects of Lightning-produced Catalysts in Eliminating Oxygen False Positives. Astrophysical Journal, 866 (1). Art. No. 56. ISSN 1538-4357. http://resolver.caltech.edu/CaltechAUTHORS:20181011-130903725

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Abstract

Over the last few years, a number of authors have suggested that, under certain circumstances, molecular oxygen (O_2) or ozone (O_3) generated by abiotic processes may accumulate to detectable concentrations in a habitable terrestrial planet's atmosphere, producing so-called "false positives" for life. But the models have occasionally disagreed with each other, with some predicting false positives, and some not, for the same apparent set of circumstances. We show here that photochemical false positives derive either from inconsistencies in the treatment of atmospheric and global redox balance or from the treatment (or lack thereof) of lightning. For habitable terrestrial planets with even trace amounts of atmospheric N_2, NO produced by lightning catalyzes the recombination of CO and O derived from CO_2 photolysis and should be sufficient to eliminate all reported false positives. Molecular oxygen thus remains a useful biosignature gas for Earth-like extrasolar planets, provided that the planet resides within the conventional liquid water habitable zone and has not experienced distinctly non-Earth-like, irrecoverable water loss.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.3847/1538-4357/aadd9bDOIArticle
ORCID:
AuthorORCID
Harman, C. E.0000-0003-2281-1990
Domagal-Goldman, S. D.0000-0003-0354-9325
Tian, F.0000-0002-9607-560X
Kasting, J. F.0000-0003-4042-2067
Alternate Title:Abiotic O2 Levels on Planets around F, G, K, and M Stars: Effects of Lightning-produced Catalysts in Eliminating Oxygen False Positives
Additional Information:© 2018 The American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Received 2017 December 1; revised 2018 August 12; accepted 2018 August 24; published 2018 October 11. This work was funded by NASA's Habitable Worlds proposal #NNX15AQ11G, and by the NASA Astrobiology Program through the Nexus for Exoplanet System Science (NExSS).
Funders:
Funding AgencyGrant Number
NASANNX15AQ11G
Subject Keywords:planet–star interactions – planets and satellites: atmospheres – planets and satellites: composition – planets and satellites: terrestrial planets
Record Number:CaltechAUTHORS:20181011-130903725
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20181011-130903725
Official Citation:C. E. Harman et al 2018 ApJ 866 56
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90250
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:11 Oct 2018 20:17
Last Modified:11 Oct 2018 20:17

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