A team of astronomers found a powerful stellar flare erupted from Proxima Centauri last March using data from (ALMA) the Atacama Large Millimeter/submillimeter Array, this discovery, published in the Astrophysical Journal Letters, raises questions in regards to the habitability of Proxima b, our solar system’s nearest exoplanetary neighbor, which orbits Proxima Centauri.
At its peak, the newly discovered flare was ten times brighter than our sun’s most massive flares, when noticed at similar wavelengths. Stellar flares haven’t been well studied at the millimeter and submillimeter wavelengths detected by ALMA, especially around stars of Proxima Centauri’s type, known as M dwarfs, which are the most common in our galaxy.
Flare then increased Proxima Centauri’s brightness by 1,000 times over 10 seconds. A smaller Flare preceded this; together, the whole event lasted fewer than two minutes of the 10 hours that ALMA noticed the star between January and March of last year.
Stellar flares occur during a shift in the star’s magnetic field accelerates electrons to speeds approaching that of light. The accelerated electrons interact with the extremely charged plasma that makes up most of the sun, causing an eruption that produces emission throughout the entire electromagnetic spectrum.
An earlier paper that additionally used the similar ALMA data interpreted its normal brightness, which added the light output of each star and the flare together, as being caused by several disks of dust encircling Proxima Centauri, not like our own solar system’s asteroid and Kuiper belts.
However, when MacGregor, Weinberger, and their team looked at the ALMA data as a function of observing time, instead of averaging all of it together, they have been able to see the transient explosion of radiation released from Proxima Centauri for what it indeed was.