b'Earth/Planetary ScienceContinued26 Questionable Habitabilityof Proxima bA team of astronomers led by Carnegies Meredith MacGregor and Alycia Weinberger detected a massive radiation explosion, a stellar flare, from the closest star to our Sun, Proxima Centauri. The observation raises questions about the habitability of our nearest exoplanet, Proxima b, which orbits Proxima Centauri.MacGregor and Weinberger, with colleagues, discovered the enormous flare when they reanalyzed last years observations by the Atacama LargePostdoctoral fellow Meredith MacGregor (left) and staff scientist Millimeter/submillimeter Array (ALMA), a radioAlycia Weinberger conducted the work on Proxima b.telescope with 66 antennas. Image courtesy Roberto Molar Candanosa, Carnegie Institution for ScienceAt peak, the flare was 10 times brighter than ourThe flare increased the stars brightness 1,000 times Suns largest flares observed at similar wavelengths.over 10 seconds. It was preceded by a smaller flare. Stellar flares have not been well studied at thoseTogether, the event lasted fewer than two minutes wavelengths, especially around otherwise normal Mof 10 hours of ALMAs observations of Proxima over dwarf stars like Proxima Centauri. many weeks.Stellar flares happen when a shift in the stars magnetic field accelerates electrons to almost light speed. The electrons interact with highly charged plasma, causing an eruption across the electromagnetic spectrumThe Proxima b planet was likely blasted by the extreme radiation flaring from its star. The star was already known to experience regular X-ray flares. The researchers used data from the Atacama Large Millimeter/ Over billions of years since forming, large flares submillimeter Array (ALMA), the largest radio telescope in thecould have evaporated any atmosphere or ocean on world. ALMA is composed of 66 antennas; some are shownProxima b and sterilized the surface, which means here. ALMA is located in the Chajnantor Plateau in the Atacama Desert, one of Earths highest and driest places.Image courtesy European Southern Observatory'