| Astrophysics (Index) | About |
Abiotic oxygen is elemental oxygen (e.g., O2) from non-biological sources. Oxygen gas is considered a biosignature, but there are also chemical processes that can generate it without the presence of living organisms, such as chemical reactions that break down water. When exoplanet atmospheres are analyzed and oxygen is detected, the planet and atmosphere's composition and temperature may suggest the oxygen could be (or is likely to be) abiotic.