The Role of Atmospheric Exchange in False-Positive Biosignature Detection

Abstract

Saturn's Moon Titan receives volatiles into the top of its atmosphere-including atomic oxygen-sourced from cryovolcanoes on Enceladus. Similar types of atmosphere exchange from one body to another, such as O2 and O3 sourced from TRAPPIST-1 d, could be introduced into the upper atmosphere of TRAPPIST-1 e and might be interpreted as biosignatures. We simulate this potential false-positive for life on TRAPPIST-1 e, by applying an external influx of water and oxygen into the top of the atmosphere using a coupled 1-D photochemical-climate model (Atmos), to predict atmospheric composition. In addition, synthetic spectral observations are produced using the Planetary Spectrum Generator for the James Webb Space Telescope, Origins Space Telescope, Habitable Exoplanet Observatory and Large Ultra-violet/Optical/Infrared Surveyor to test the detectability of abiotic-generated O2 and O3 in the presence of abiotic and biotic surface fluxes of CH4. We determine that the incoming flux of material needed to trigger detection of abiotic O2/O3 by any of these observatories is more than two orders of magnitude (1E12 molecules/cm2/s) above what is physically plausible.

23 pages, 5 figures. An edited version of this paper was published by AGU. Copyright (2022) American Geophysical Union

References in corpus (14)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• The Pale Orange Dot: The Spectrum and Habitability of Hazy Archean Earth
• Tidal Locking of Habitable Exoplanets
• Abiotic Ozone and Oxygen in Atmospheres Similar to Prebiotic Earth
• The Habitable Exoplanet Observatory (HabEx) Mission Concept Study Final Report
• Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets
• Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System
• The LUVOIR Mission Concept Study Final Report
• Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets Around Low-Mass Stars: the TRAPPIST-1 System
• The Mega-MUSCLES Spectral Energy Distribution Of TRAPPIST-1
• Imaging low-mass planets within the habitable zone of α Centauri
• Sensitive Probing of Exoplanetary Oxygen via Mid Infrared Collisional Absorption
• Origins Space Telescope Mission Concept Study Report

Cited by in corpus (2)

• Alternative Methylated Biosignatures I: Methyl Bromide, A Capstone Biosignature
• Atmospheric carbon depletion as a tracer of water oceans and biomass on temperate terrestrial exoplanets