Resolved imaging confirms a radiation belt around an ultracool dwarf.

Radiation belts are present in all large-scale Solar System planetary magnetospheres: Earth, Jupiter, Saturn, Uranus and Neptune. These persistent equatorial zones of relativistic particles up to tens of megaelectron volts in energy can extend further than ten times the planet's radius, emit gradually varying radio emissions and affect the surface chemistry of close-in moons. Recent observations demonstrate that very low-mass stars and brown dwarfs, collectively known as ultracool dwarfs, can produce planet-like radio emissions such as periodically bursting aurorae from large-scale magnetospheric currents.