The exoplanet Proxima b has been hit by a massive stellar flare from its host star, Proxima Centauri, wiping out any hopes that the planet might have harbored signs of life.
Astronomers announced that the extraordinarily powerful flare “likely blasted” the exoplanet with “high energy radiation,” according to Meredith MacGregor of the Carnegie Institution for Science, who led the research with fellow Carnegie astronomer Alycia Weinberger, along with with colleagues from the Harvard-Smithsonian Center for Astrophysics, David Wilner and Adam Kowalski, and Steven Cranmer of the University of Colorado Boulder.
This was not the first time this happened. Scientists say that it’s likely Proxima b was bombarded with similar flares for billions of years, Forbes reports.
Over the billions of years since Proxima b formed, flares like this one could have evaporated any atmosphere or ocean and sterilized the surface, suggesting that habitability may involve more than just being the right distance from the host star to have liquid water,
MacGregor said. “We observed for only ten hours and caught this one. So you can extrapolate—and imagine these flares might be relatively common.”
This means Proxima b is a dead world. The flare took place a year ago, in March 2017. At its highest point, Proxima Centauri’s brightness likely increased by as much as a thousand times.
Flares of this enormous level are capable of eventually obliterating any atmosphere a planet has, essentially sterilizing the landscape. With no atmosphere to speak of, there is no possibility of liquid water, which sustains life.
“This certainly raises questions about possible habitability,” MacGregor said.
But there are other things that might still make extraterrestrial life possible, the scientists added. MacGregor said, “There are a lot of factors we still don’t understand. I hesitate to immediately squash it (the possibility of life).”
The team analyzed data from the Atacama Large Millimeter/submillimeter Array (ALMA) Observatory in Chile. Stellar flares have not been thoroughly observed at the millimeter and submillimeter wavelengths identified by ALMA.
The study was published in The Astrophysical Journal Letters.
