About 60 light years away a pair of red dwarf stars, each roughly one-third the size of the sun, are locked in a close binary systems. The stars, known as DG Canum Venaticorum, or DG CVn rotate each other at a distance of about 3 times that between the Earth and our sun.

At 5:07 Eastern Daylight Time on April 23 a rising tide of X-rays from the system triggered the Swift Satellite’s Burst Alert Telescope (BAT). When the BAT detects strong radiation, it swiftly calculates the origin, decides whether it merits further investigation and, if so, sends it’s position to the spacecraft.

“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. Flares this large from red dwarfs are exceedingly rare,” said Adam Kowalski of NASA’s Goddard Space Flight Center in a statement.

The initial blast was 10,000 times more powerful than anything detected to date. Researchers estimate that at its peak the flare’s temperature reached 360 million degrees Fahrenheit, or about 12 times hotter than the center of the sun. Three hours after the initial blast a second eruption, almost as large as the first, was detected. Successively weaker blast were detected for an additional 11 days.

Solar flares occur around the active regions of a stars atmosphere. Magnetic fields get twisted, similar to the twisting of a rubber band, and allow energy to accumulate until they are suddenly straightened causing a sudden explosion of energy. Flares are classified in terms of their intensity, with X class flares being the largest.

“The biggest flare we’ve ever seen from the sun occurred in November 2003 and is rated as X 45. The flare on DG CVn, if viewed from a planet the same distance as Earth is from the sun, would have been roughly 10,000 times greater than this, with a rating of about X 100,000,” said Stephen Drake, an astrophysicist at Goddard.

Although they are much smaller than our sun, red dwarf stars are able to generate strong magnetic fields because they spin at a much faster rate, in the case of DG CVn about 30 times faster than the sun.

Researchers are now studying the data from the flares in order to better understand the event and the lives of young stars more generally. NASA’s swift will continue paying special attention to the system in case of future eruptions.

“This system is poorly studied because it wasn’t on our watch list of stars capable of producing large flares. “We had no idea DG CVn had this in it,” said Rachel Osten, an astronomer at the Space Telescope Science Institute in Baltimore and a deputy project scientist for NASA’s James Webb Space Telescope, now under construction.