Brown dwarfs often get a bad rap for being "failed stars" or "sub-stellar objects," but in light of new research they may finally be known as "over-achieving planets." Scientists have used a radio antenna array in Europe to detect evidence that some brown dwarfs may glow with powerful aurorae.
We know an aurora as the beautiful and sometimes dramatic glow that appears at high latitudes when the sun's highly-charged particles interact with our planet's global magnetosphere. The solar wind and explosive events like coronal mass ejections (CMEs) will carry solar plasma (primarily energetic protons) out to the Earth's orbit. Often, they will interact with the geomagnetic field and spiral down toward the poles (where the magnetic field is directed). On interacting with the atmosphere, light is generated, producing the aurora we know and love.
However, before the particles are absorbed by the atmosphere, creating auroral light, spiraling plasma will generate radio emissions that can be detected. It stands to reason that any planetary body with a global magnetic field should have their own aurorae and also generate a radio hum. Indeed, astronomers are very familiar with aurorae on Jupiter and Saturn - Jovian auroral displays known to be 100 times more intense than anything Earth's atmosphere can generate and their associated radio emissions can be studied.