We have recently seen EK Draconis spew out a super-eruption accompanied by a mammoth coronal mass ejection. It was a heavenly show and also a warning. The star in question is a young and therefore much more turbulent version of the Sun, but we should still be careful. It is only a matter of time before such a dragon’s roar arrives at Earth again.
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The EC star Draconis in the constellation Dragon is a 100 million year old version of our Sun. This stellar cub recently launched an extreme eruption of magnetic plasma, the power of which is ten times greater than anything we have ever seen from stars like the Sun. It was as if a mighty dragon from Middle-earth had spewed fire. It was a breathtaking spectacle and a warning at the same time. Now we know what stars of this kind can do. And we should take that into account.
Yuta Notsu. Kredit: University of Colorado, Boulder.
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Astronomer Yuta Notsu of the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder and his colleagues are convinced that even the Sun can probably roar and detonate a mammoth coronal mass (CME) outburst. Fortunately, the sun is much older than EK Draconis, so it’s probably calmer and does things less often.
It is certainly good that we know how strong such coronal mass ejections can be. We can estimate what damage they would do. Geomagnetic storms would be a matter of course, which could knock out satellites, cause blackouts of electricity and silence the Internet and other forms of communication. It’s not just about the Earth. An event of similar magnitude as we have now seen at EC Draconis could literally fry any person or device that is struck outside the Earth’s protective geomagnetic field. It would be like undergoing 300,000 chest X-rays at once.
Notsu et al. they have previously discovered that Sun-like stars can fire super-eruptions. When it comes to young stars, it’s okay every week. Adult stars, such as the Sun, could fire such eruptions, we firmly hope, only about once every 1,000 years. But hard to say yet.
Logo. Kredit: University of Colorado, Boulder.
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Supereruptions alone are not that dangerous. The real problem occurs when a super-eruption is accompanied by a super-jet of coronal mass. Notsu and his colleagues were looking for just such a case. Using the US Transiting Exoplanet Survey Satellite (TESS) and Japan’s SEIMEI Telescope, they observed the star EK Draconis, about 111 light-years away, between January and April 2020. They saw a shift in the EC’s Draconis radiation spectrum on April 5. , corresponding to the large outpouring of plasma flying towards us. The outflow was 1.6 million kilometers per hour and its total weight was about 1 trillion kilograms. That goes beyond anything we’ve ever seen in the Sun.
Video: Yuta Notsu: Do superflares occur on the Sun?
Literature
Nature Astronomy online 9. 12. 2021.
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