An international team led by Peking University and ASTRON has discovered a new type of radio emission from the red dwarf AD Leo, the most common type of star in our Galaxy (Jiale Zhang et al., Science Advances 2025). Using China’s FAST telescope, they observed millisecond-long bursts whose frequencies sweep at an astonishing 8 GHz per second – far faster than expected.
These fast sweeps reveal tiny magnetic arches anchored on starspots, regions of intense magnetic activity that can trigger stellar flares and shape the space weather around orbiting exoplanets. Until now, such small-scale magnetic structures were impossible to study directly in distant stars. The team plans to use this technique on other stars to study stellar eruptions and space-weather impacts on exoplanets.
Image: FAST detects radio bursts from small, active magnetic arches on red dwarf AD Leo.