A star doesn’t have to be big to be brash. Indeed, some of the most active stars are also some of the smallest.
An example is in Lacerta, the lizard. The constellation is high in the northeast at nightfall. It’s not much to look at — only a few puny stars outline the lizard’s profile.
But about a decade ago, one of its stars really showed off. It produced the most powerful stellar flare seen to that time — thousands of times more powerful than anything the Sun has generated.
Flares are massive explosions. They occur when lines of magnetic force get tangled, then snap. Some of the biggest happen in little stars.
EV Lacertae, for example, is a red dwarf. It’s only about a third as massive as the Sun, and just one percent as bright. A red dwarf is different from stars like the Sun. Hot gas bubbles from its core all the way to the surface. The gas is electrically charged. So as it churns, it generates a strong magnetic field. And EV Lacertae is quite young, so it spins faster than the Sun does. That amps up the magnetic field even more.
With a faster-spinning magnetic field, the lines are bound to get more tangled. And when they snap, they do so with a jolt — a giant flare. It blasts energy and particles into space.
If the Sun zapped Earth with such a flare, it could knock out everything from cell phones to power grids — decimating our technology in an instant.
We’ll talk about an even more powerful object in Lacerta tomorrow.