Year: 2014
Type: article
Abstract: Detection of life on other planets requires identification of biosignatures, i.e., observable planetary properties that robustly indicate the presence of a biosphere. One of the most widely accepted biosignatures for an Earth-like planet is an atmosphere where oxygen is a major constituent. Here we show that lifeless habitable zone terrestrial planets around any star type may develop oxygen-dominated atmospheres as a result of water photolysis, because the cold trap mechanism that protects H 2 O on Earth is ineffective when the atmospheric inventory of non-condensing gases (e.g., N 2 , Ar) is low. Hence the spectral features of O 2 and O 3 alone cannot be regarded as robust signs of extraterrestrial life.
Authors: Robin Wordsworth, Raymond Pierrehumbert
Institution: University of Chicago
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W2101682039