One of Earth’s closest exoplanets, Proxima B, was hit by a massive solar flare generated by its host star, Proxima Centauri. The event reportedly occurred on March 24, 2017.
According to the research paper detailing the event, Proxima Centauri unleashed a flare that made the star appear one thousand times brighter than usual and lasted for 10 seconds. Scientists argue that such outbursts are common and that similar solar flares may have bombarded Proxima B for possibly billions of years.
“Over the billions of years since Proxima b formed, flares like this one could have evaporated any atmosphere or ocean and sterilized the surface,” said Meredith MacGregor, first author of the study and an astronomer at the Carnegie Institution for Science.
MacGregor also suggests that Proxima b was blasted by high energy radiation during this flare, meaning that the planet could have resorted back to a rock devoid of life.
Ever since its discovery in August 2016, Proxima b was considered a prime candidate for sustaining life mainly due to its Earth-like size, terrain and proximity to its star. In addition to its Earth-like features, Proxima b was our nearest exoplanet, at 4 light years away, or about twenty-five trillion miles away.
However, if this planet was an archetype for habitable exoplanets then scientists would need to take into account stellar flares that can routinely wipe out their atmospheres. This would mean that every exoplanet discovered so far would have to be re-evaluated.
Our sun is also known to produce the occasional flare, however, Proxima Centauri is believed to be a lot more active than our host star.
Proxima Centauri is an M-dwarf star, a class that is very common in our galaxy. Scientists think these red stars are too volatile in their early years especially when it comes to hosting life.
The study was published in The Astrophysical Journal Letters.
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