Records – of a seemingly tiny, almost Jupiter-sized star.
The Next Generation Transit Survey (NGTS), a celestial survey telescope in Chile, first discovered the torch on August 13, 2017. Not only It's the second largest torch observed, coming from a L-dwarf star, but this is the coolest star ever to show this kind of powerful torch.
The star named ULAS J224940.13-011236.9 is an L dwarf, a red star about 250 light-years away that is only 10 percent of the Sun's radius. It burns at temperatures as low as 1,930 degrees Kelvin – about the temperature of a blowtorch. Stars like these are too cold to be detected by the NGTS – until one of them triggers a giant torch that appears in the survey. If this is the case, the researchers group the position of the flare with the list of known star positions from the two-micron all-sky survey called 2MASS.
After finding the culprit, researchers must use a model to compute the star's amplitude, duration, and energy of the torch. They ended with a flash that lasted nearly 10 minutes, releasing energy of 3.4 * 10 33 . If such an eruption occurred on our own sun, it would cause a whole series of power outages here on Earth.
These fascinating results are published in the Monthly Notices of the Royal Astronomical Society.
The numbers, of course, are not accurate because they are based on modeling that is subject to inevitable human prejudices. Still, a star too weak to appear on the NGTS appeared ten thousand times brighter in a flashlight, which is wild.
Scientists believe that strong torches like these develop when parts of the star's magnetic fields are in opposite orientations. This heats particles in the equivalent of the atmosphere of the star, releasing the emission of "white light". Other dwarf stars also experience strong torches, but none of these stars is as cool as this one.
The scientists behind the new paper were thrilled that the NGTS study could investigate large torches on such stars and say that this could change. So we think about small stars. I'm just proud of the little guy.