Radiation makes Earth-like planet uninhabitable

The most Earth-like planet ever found could have been made uninhabitable by vast quantities of radiation superflares 10 times more powerful than those recorded on the Sun, a new study has found.

The atmosphere of the planet, Kepler-438b, is thought to have been stripped away as a result of radiation emitted from a superflaring Red Dwarf star, Kepler-438, researchers said.

Regularly occurring every few hundred days, the superflares are approximately 10 times more powerful than those ever recorded on the Sun and equivalent to the same energy as 100 billion megatonnes of TNT.

While superflares themselves are unlikely to have a significant impact on Kepler-438b’s atmosphere, a dangerous phenomenon associated with powerful flares, known as a coronal mass ejection (CME), has the potential to strip away any atmosphere and render it uninhabitable.

The planet Kepler-438b, to date the exoplanet with the highest recorded Earth Similarity Index, is both similar in size and temperature to the Earth but is in closer proximity to the Red Dwarf than the Earth is to the Sun.

“Unlike the Earth’s relatively quiet sun, Kepler-438 emits strong flares every few hundred days, each one stronger than the most powerful recorded flare on the Sun. “It is likely that these flares are associated with coronal mass ejections, which could have serious damaging effects on the habitability of the planet,” lead researcher, Dr David Armstrong of the University of Warwick’s Astrophysics Group, said.

“If the planet, Kepler-438b, has a magnetic field like the Earth, it may be shielded from some of the effects. However, if it does not, or the flares are strong enough, it could have lost its atmosphere, be irradiated by extra dangerous radiation and be a much harsher place for life to exist,” said Dr Armstrong.