Don’t pack your bags for Proxima Centauri just yet. Astronomers have seen the star emit a superflare that briefly made it 68 times brighter than usual, and could expose any life on the surface of its orbiting Earth-sized planet to fatal levels of UV radiation.
at the University of North Carolina at Chapel Hill and his colleagues spotted the flare in data from March 2016. It was ten times as energetic as any previously seen erupting from Proxima Centauri and made the star just about visible from Earth with the naked eye – albeit only to people with impeccable vision and a completely dark sky.
“For the vast majority of people, even in very clear conditions, optical aid would be needed,” says at the University of Oxford. The star is a red dwarf just 4.3 light years away from us with an Earth-sized planet called Proxima Centauri b orbiting in the habitable zone. We already knew that it was prone to outbursts of X-rays and UV radiation that dampen life’s chances of survival.
Advertisement
Now, looking through data from an array of telescopes called the at the University of North Carolina at Chapel Hill, astronomers have witnessed one of its superflares for the first time. “I’d expected that we’d see a superflare, and it was there, so that was really reassuring,” says Howard.
Hell or high water
Over two years the researchers saw 23 more flares. They estimate that Proxima Centauri will emit up to five superflares each year. Assuming the planet has an Earth-like atmosphere, within five years the radiation from the flares would wipe out 90 per cent of its ozone. That would leave even UV-hardy organisms exposed to fatal levels of radiation.
But there are still many unknowns about Proxima Centauri b, including whether it has an atmosphere at all. This research isn’t necessarily the end of hope for life on the planet.
“There might be other atmospheric compositions and ways to block UV,” says at Columbia University in New York, such as a haze similar to that which may have enveloped the early Earth. The planet could also have an ocean, which would be able to keep organisms safe. “Marine environments just a little beneath the surface might be well shielded from most UV,” he says.
Reference:
Read more: Our closest star system may be home to a stolen star and planet
