Within seconds, the star became as much as 14,000 times (!) Brighter at ultraviolet wavelengths.
We have known for some time that Proxima Centauri – the closest star to our solar system – produces solar flares. But the fact that the star also spawns monstrous variants was a total surprise. Scientists recently detected the largest solar flare ever to come from Proxima Centauri. And it also has consequences for our hunt for extraterrestrial life.
Learn more about Proxima Centauri
As mentioned, the star Proxima Centauri is located at a relatively short distance from Earth. For example, the star is only 4 light years away. To our knowledge, Proxima Centauri is home to two planets, one of which could be quite similar to Earth. In addition, the star is a so-called red dwarf; they are the most common and oldest stars in the universe. Red dwarfs are much cooler than our sun and have less mass. For example, Proxima Centauri has about one-eighth the mass of our own sun.
Proxima Centauri is a small but powerful star. We should certainly not underestimate him. In the study, published in the journal Letters from the astrophysical journal, the researchers observed the nearby star for 40 hours using no less than nine telescopes, including the Hubble Space Telescope, the Atacama Large Millimeter / submillimeter Array and the TESS planet hunter. And as they were looking at the star, something striking happened.
The researchers found that Proxima Centauri suddenly produced a gigantic solar flare. This is a huge burst of energy on the surface of a star. “Within seconds, the star became up to 14,000 times brighter at ultraviolet wavelengths,” said Meredith MacGregor, study leader. In fact, the monstrous solar flare was one of the most violent scientists have ever seen. For example, the observed solar flare was about 100 times more powerful than any similar specimen. The entire event only lasted seven seconds.
The powerful radiation emitted during a solar flare has far-reaching consequences for nearby planets. Because it is very likely that such a planet will be bombarded with high energy particles during the solar flare. This means that planets can even be completely dismantled from their atmosphere, exposing life forms to deadly radiation. “If there is life on the planet closest to Proxima Centauri, it probably looks very different from Earth,” MacGregor says. “A human on this planet would have had a terrible time.”
As mentioned, the occurrence of solar flares on Proxima Centauri is anything but a rarity. During the 40 hours that the researchers looked at the star, they also saw numerous solar flares – although of different orders -. “The planets around Proxima Centauri are bombed at least once a day, but not multiple times a day,” MacGregor said.
Although little visible light was produced during the solar flare, it generated ultraviolet and radio or “millimeter” rays. “In the past, we didn’t know there was activity even at these millimeter wavelengths,” says MaGregor. “This is the first time that we have researched solar flares at these millimeter wavelengths.” Researchers currently suspect that solar flares are caused by a sudden change in a star’s magnetic field. But the observed millimeter signals could potentially reveal more important information about exactly how stars generate these powerful bursts of energy.
The results of the study suggest that the free-flying star Proxima Centauri may have even more surprises in store for us. “There will probably be other weird types of solar flares that show different types of physics that we haven’t thought about until now,” MacGregor says. Time will tell us.
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