What Impact Does Ozone Have on an Exoplanet?

Artist's illustration of Proxima Centauri b. ESO/M. Kornmesser

As we discover more and more exoplanets – and the current total is in excess of 5,200 – we continue to try to learn more about them. Astrobiologists busy themselves analysing their atmospheres searching for anything that provides a sign of life. It is quite conceivable of course that the Universe is teeming with life based on very different chemistry to ours but we often look to life on Earth to know what to look for. On Earth for example, ozone forms through photolysis of molecular oxygen and is an indicator of life. Using the James Webb Space Telescope astronomers are searching stars in the habitable zone of their star for the presence of ozone and how it impacts their climate.

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What Could the Extremely Large Telescope See at Proxima Centauri's Planet?

Artist’s impression of the surface of the planet Proxima b orbiting the red dwarf star Proxima Centauri. The double star Alpha Centauri AB is visible to the upper right of Proxima itself. Credit: ESO

Proxima Centauri B is the closest exoplanet to Earth. It is an Earth-mass world right in the habitable zone of a red dwarf star just 4 light-years from Earth. It receives about 65% of the energy Earth gets from the Sun, and depending on its evolutionary history could have oceans of water and an atmosphere rich with oxygen. Our closest neighbor could harbor life, or it could be a dry rock, but is an excellent target in the search for alien life. There’s just one catch. Our usual methods for detecting biosignatures won’t work with Proxima Centauri B.

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