科学美国人60秒:Flare Star Goes Wild In Minutes

Imagine if your living room zoomed from a comfy 70 degrees to 3,000. In less time than it usually takes to boil an egg. Well, a star did the equivalent—it went from 5,000 degrees Fahrenheit to 30,000 degrees in less than three minutes. And got 15 times brighter in the process.

Sixteen light-years away, the star WX Ursa Majoris is what’s called a “flare star.” It’s usually a red dwarf: cooler, fainter and smaller than the sun. But every so often, it goes wild.

Why certain stars flare remains a mystery. But astronomers think it starts with a disruption in the star’s magnetic field. Parts of the field twist, break and reconnect. As they do, energy gets pumped into the star’s atmosphere, and the candle becomes a searchlight. The observations are in the journal Astrophysics. [N.D. Melikian et al, Spectral observations of flare stars in the neighborhood of the sun]

WX orbits another, bigger star. Astronomers are watching to see if that neighbor is an instigator. Should future flares sync to the stars’ orbits, we’ll gain insights into flare stars and on how binary stars affect one another. The research should shed some light.

—Chris Crockett

[The above text is a transcript of this podcast]