Flares From Proxima B’s Star Could Affect The Planet’s ‘Habitability’
The European Southern Observatory (ESO) has just recently confirmed the discovery of a potentially habitable planet orbiting Proxima Centauri, a few light years away from Earth.
But researchers have discovered massive bursts of energy from Proxima b's red dwarf star, Proxima Centauri, and that the flares could be impacting the planet's atmosphere. According to the scientists, who detailed their findings in a study published in arxiv, these energy bursts might reduce the planet's ability to sustain life.
"We knew it would have flares, but we didn't realize it would be as riddled with flares as it is," James Davenport, a scientist at the Western Washington University in Bellingham, said in a report by New Scientist.
Davenport and his team were studying Proxima Centauri using the Canadian MOST (Microvariability and Oscillation of Stars) space telescope when they found that the star is constantly flaring up, approximately every 20 minutes.
The researchers are hoping to use MOST to detect Proxima b as it transits or passes in front of Proxima Centauri to help determine its size and to get a glimpse of the planet's atmosphere, which could indicate signs of life in the planet. But the flares coming from red dwarf star make it harder to observe the transits.
Scientists used MOST to observe Proxima Centauri for 38 days between 2014 and 2015. During the observation period, the research team found 66 flares of different sizes, majority of which caused a 5 to 10 percent increase in brightness and sometimes increasing to 50 percent. The smaller flares were even bigger in comparison with the flares coming from the Sun.
Davenport and his team have made their analysis based on previous modeling of planets around flaring stars, and have concluded that Proxima Centauri's "superflares" could be destructive to the potential atmosphere of Proxima b.
"If you are getting hit every couple of months, the atmosphere is never going to recover, so you are going to see slow degrading of it," Davenport said.
Proxima b would be able to resist the blasts and protect life in it if its atmosphere is thick enough and if it has a magnetic field, Davenport said.
Also, scientists said that continuous bombardment could "erode or severely alter the chemistry" of any atmosphere, which leaves the planet's surface vulnerable to deadly radiation.
"If the atmosphere is thinner, then more UV radiation will hit the ground," Lisa Kaltenegger from Cornell University, who was not part of the research, said in a report from National Geographic. "Ground-based life will either have to shelter underground, underwater, or rely on another mechanism to shield itself."
According to Gavin Coleman of Queen Mary University of London, who was part of the team that discovered Proxima b, the findings put "limits on the probability of habitability."
Scientists will continue to assess whether Proxima b has an atmosphere capable of sustaining life by observing the planet through a transit. According to Davenport, the MOST data for transits will be fully analyzed within the next few months.