NASA's swift satellite recently detected the strongest and hottest sequence of solar flares ever seen from a close-by red dwarf star.
The finding, made on April 23, revealed a solar blast about 10,000 times more powerful than the largest ever recorded by scientists, the NASA/Goddard Space Flight Center reported.
"We used to think major flaring episodes from red dwarfs lasted no more than a day, but Swift detected at least seven powerful eruptions over a period of about two weeks," said Stephen Drake, an astrophysicist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who gave a presentation on the "superflare" at the August meeting of the American Astronomical Society's High Energy Astrophysics Division. "This was a very complex event."
The flare, located about 60 light-years from Earth, reached a peak temperature of 360 million degrees Fahrenheit, which is a scorching 12 times hotter than the center of our Sun.
The flare took place in a binary star system DG CVn, which has been so scarcely studied it was not even on the researchers' "watch list" of stars that might emit spectacular solar flares.
Stars erupt with solar flares when magnetic regions in their atmosphere become twisted, causing energy to accumulate. Once the energy is built up, a process called "magnetic reconnection" destabilizes the fields, causing an explosion. The event emits radiation across the electromagnetic spectrum.
The giant "superflare" triggered Swift's Burst Alert Telescope (BAT), which quickly calculated its location.
"For about three minutes after the BAT trigger, the superflare's X-ray brightness was greater than the combined luminosity of both stars at all wavelengths under normal conditions," said Goddard's Adam Kowalski, who is leading a detailed study on the event. "Flares this large from red dwarfs are exceedingly rare."
Three hours after the initial outburst, the system emitted another flare almost as intense as the first one, followed by a series of weaker flashes over the next 11 days. Researchers believe the star was able to give off such a strong flare because it rotates in under a day, which is 30 times faster than our own Sun, amplifying magnetic fields. The Sun rotated much faster in its youth, and may have emitted flares of an equal caliber.
