The nearest star to the sun, the Proxima Centauri, bombarded a planet in its habitable zone called the Proxima B, with a massive stellar flare in March 2017, a team of scientists has found out.
During the event, Proxima Centauri became 1,000 times brighter than it normally is.
The flare likely bathed Proxima B in radiation, which is not good news for the planet's potential to host life.
The study, led by Alycia Weinberger and Meredith MacGregor, was published in the journal Astrophysical Journal Letters.
The discovery raises questions about the habitability of the Proxima B, which is the nearest exoplanetary neighbor of the solar system.
The research team observed the gigantic flare when they restudied the observations taken by the Atacama Large Millimeter/submillimeter Array last year. ALMA is a radio telescope comprising off 66 antennae.
Proxima Centauri Emits Massive Stellar Flare
The stellar flare emitted by Proxima Centauri was 10 times brighter than the largest flares generated by the sun when observed at similar wavelengths at peak luminosity.
"March 24, 2017 was no ordinary day for Proxima Cen. It's likely that Proxima b was blasted by high energy radiation during this flare," said MacGregor.
Stellar flares occur when a shift in the magnetic field of a star accelerates electrons to nearly the speed of light. The interaction of the accelerated electrons with the highly charged plasma, which makes up a majority of the star, causes an eruption that generates emission across the whole electromagnetic spectrum.
An earlier study, which also used the same data from ALMA, found that the Proxima Centauri's average brightness was a result of the multiple dusk discs encircling the star, similar to the effect produced by the Kuiper and asteroid belts in the solar system. The authors associated with that study said that the presence of dust indicated that more planets or planetary bodies existed in the Proxima Centauri system.
The new study, however, says that there is no reason to think that there is a good amount of dust around the star and that the brightness was due to the transient explosion of radiation. The research team also added that they still do not have any information that could indicate that the Proxima B star system is as rich as the solar system.
Proxima Centauri's Stellar Flare Detrimental To Proxima B's Chances Of Life
MacGregor added that massive stellar flares, like the one recently seen, could have evaporated any ocean or atmosphere and sterilized the surface over the billions of years since the exoplanet formed. It also indicates that the habitability quotient of a planet involves much more than just being located at the right distance from its parent star to have liquid water.
