Massive Stellar Flares From a Very Mini Star
NASA's Swift satellite recently observed one of the most intense and longest-lasting sequences of stellar flares ever seen coming from a red dwarf star. Experts are even reporting that the series of eruptions were up to 10,000 times more powerful than the strongest of our Sun's recorded solar flares.
According to NASA, the strongest of these stellar flares reached temperatures of 360 million degrees Fahrenheit (200 million Celsius). That's more than 12 times hotter than the center of the Sun.
Stephen Drake, an astrophysicist at NASA's Goddard Space Flight Center, also said this "superflare" event lasted far longer than anyone had expected.
"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," he said at the meeting of the American Astronomical Society's High Energy Astrophysics Division last August.
So just what happened here? The flare reportedly came from one of the stars in a close binary system known as DG Canum Venaticorum (DG CVn), located about 60 light-years away. The system is unusual for binaries, as it boasts two red dwarf stars that are no larger than one-third of our Sun's size.
"This system is poorly studied because it wasn't on our watch list of stars capable of producing large flares," Rachel Osten, an astronomer at the Space Telescope Science Institute in Baltimore, explained in a recent statement. "We had no idea DG CVn had this in it."
Still, despite being dim and small red dwarves, the DG CVn stars are pretty young - only about 30 million years old - and just like children, young stars are far more active and unpredictable compared to how they will be in middle-age.
According to NASA experts looking at Swift satellite data, the uncharacteristic flare event began around 5:07 pm EDT back on April 23 and continued on for an estimated 11 days. And while Swift was able to measure the intense and record-breaking stellar activity, it was unable to tell which of the two dwarves caused the activity, or if it was the result of an unusual interaction between the two.
You can watch a video of Drake and Osten detailing the remarkable event and speculating about what could have caused it below.
[Credit: NASA's Goddard Space Flight Center/S. Wiessinger]