It may also not bode well for life on Earth: The team's findings hint that the sun could also be capable of such violent extremes. But even so, it was a monster, moving at a top speed of roughly 1 million miles per hour. The researchers were only able to catch the first step in that ejection's life, called the "filament eruption" phase. About 30 minutes later, the team observed what appeared to be a coronal mass ejection flying away from the star's surface. On April 5, Notsu and his colleagues got lucky: The researchers looked on as EK Draconis erupted into a superflare, a really big one. The researchers observed the star for 32 nights in winter and spring 2020 using NASA's Transiting Exoplanet Survey Satellite (TESS) and Kyoto University's SEIMEI Telescope. "It's what our sun looked like 4.5 billion years ago," Notsu said. The curious star, Notsu explained, is about the same size as our sun, but, at just 100 million years old, it's a relative youngster in a cosmic sense. To find out, the researchers set their sights on EK Draconis. But until recently, that was just conjecture." "So we suspect that they would also produce much bigger mass ejections. "Superflares are much bigger than the flares that we see from the sun," Notsu said. Still, it got Notsu's team curious: Could a superflare also lead to an equally super coronal mass ejection? Such a superflare could, theoretically, also happen on Earth's sun but not very often, maybe once every several thousand years. In 2019, for example, Notsu and his colleagues published a study that showed that young sun-like stars around the galaxy seem to experience frequent superflares-like our own solar flares but tens or even hundreds of times more powerful. Recent research, however, has suggested that on the sun, this sequence of events may be relatively sedate, at least so far as scientists have observed. Notsu explained that coronal mass ejections often come right after a star lets loose a flare, or a sudden and bright burst of radiation that can extend far out into space. "This observation may help us to better understand how similar events may have affected Earth and even Mars over billions of years." "This kind of big mass ejection could, theoretically, also occur on our sun," Notsu said. The event may serve as a warning of just how dangerous the weather in space can be. In April 2020, the team observed EK Draconis ejecting a cloud of scorching-hot plasma with a mass in the quadrillions of kilograms-more than 10 times bigger than the most powerful coronal mass ejection ever recorded from a sun-like star. In that research, Namekata, Nostu and their colleagues used telescopes on the ground and in space to peer at EK Draconis, which looks like a young version of the sun. The new study, led by Kosuke Namekata of the National Astronomical Observatory of Japan and formerly a visiting scholar at CU Boulder, also suggests that they can get a lot worse. "Coronal mass ejections can have a serious impact on Earth and human society," said Notsu, a research associate at the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder and the U.S. And they're potentially bad news: If a coronal mass ejection hit Earth dead on, it could fry satellites in orbit and shut down the power grids serving entire cities.
Notsu explained that the sun shoots out these sorts of eruptions on a regular basis-they're made up of clouds of extremely-hot particles, or plasma, that can hurtle through space at speeds of millions of miles per hour. The study explores a stellar phenomenon called a "coronal mass ejection," sometimes known as a solar storm. The researchers, including astrophysicist Yuta Notsu of the University of Colorado Boulder, will publish their results Dec.
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