Radiation makes life impossible in most earth like planets
December 11, 2015
Vast amounts of radiation may be making life impossible on a planet that is considered the most Earth-like known outside our solar system, new research claims.
Scientists say radiation from a “superflaring” red dwarf star, dubbed Kepler-438 may have stripped away the atmosphere of the planet, Kepler-438b.
Regularly occurring every few hundred days, the superflares are about ten times more powerful than those ever recorded on the Sun, and equivalent in energy to tens of billions of nuclear bombs, according to the researchers, from the University of Warwick in the U.K.
The danger to the planetary atmosphere isn’t the flares themselves, he added, but an associated phenomenon known as coronal mass ejections, in which a star throws off giant blobs of stellar material called plasma.
The resulting loss of atmosphere “could have serious damaging effects on the habitability of the planet,” said astrophysicist David Armstrong at the university, lead researcher of the research, published in the journal Monthly Notices of the Royal Astronomical Society.
“The presence of an atmosphere is essential for the development of life,” added Chloe Pugh of the university, a collaborator in the project.
Kepler-438b, the planet with the highest recorded “Earth Similarity Index,” is both similar in size and temperature to the Earth but is closer to its small star than the Earth is to the Sun.
“If the planet, Kepler-438b, has a magnetic field like the Earth, it may be shielded from some of the effects,” Armstrong said. But “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.”
“Coronal mass ejections are where a huge amount of plasma is hurled outwards from the Sun,” said Pugh. “There is no reason why they should not occur on other active stars as well. The likelihood of a coronal mass ejection occurring increases with the occurrence of powerful flares, and large coronal mass ejections have the potential to strip away any atmosphere that a close-in planet like Kepler-438b might have, rendering it uninhabitable. With little atmosphere, the planet would also be subject to harsh UV and X-ray radiation from the superflares, along with charged particle radiation, all of which are damaging to life.”
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