Proxima B May Not Be Such a Great Second Home For Humanity After All

Since its discovery was announced in the summer of 2016, the exoplanet Proxima b has been the darling of post-Earth dreamers hoping to find new homes for humanity (within a reasonable cosmic commute).

Becky Ferreira | MOTHERBOARD

Proxima b seemed like the perfect fit—it is Earth-sized and orbits within the habitable zone of the closest star to the Sun, the M-class red dwarf Proxima Centauri, which is four light years distant. These bonuses have made it a central target of the $100 million Breakthrough Starshot mission, funded by billionaire Yuri Milner, which aims to send tiny spacecraft to other star systems.

But from the get-go, many scientists have raised red flags about the potential habitability of Proxima b, focusing in particular on the proclivities of red dwarfs. Though these stars outlive stars like the Sun for billions of years, they also commonly barf out highly energetic flares capable of irradiating nearby planets into sterility.

Now, research led by Meredith MacGregor, an astronomer at the Carnegie Institution for Science, confirms this hunch with a detection of a colossal flare from Proxima Centauri that occurred on March 24, 2017. In a paper published Monday in the Astrophysical Journal Letters, MacGregor and her co-authors present observations of the event, recorded by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.

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