  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.
