A resolved outflow of matter from a brown dwarf

The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows1,2. Although this phenomenon has been seen in young stars, a fundamental question is whether it also occurs among newborn brown dwarfs: these are the so-called ‘failed stars’, with masses between stars and planets, that never manage to reach temperatures high enough for normal hydrogen fusion to occur3. Recently, evidence for accretion in young brown dwarfs has mounted4,5,6, and their spectra show lines that are suggestive of outflows7,8,9. Here we report spectro-astrometric data that spatially resolve an outflow from a brown dwarf. The outflow's characteristics appear similar to, but on a smaller scale than, outflows from normal young stars. This result suggests that the outflow mechanism is universal, and perhaps relevant even to the formation of planets