FAILED stars may be more common than anyone thought. If so, it would change our idea of how stars form.

In 2007, a star near the centre of our galaxy appeared to brighten because another object had focused the star’s light onto Earth. From the way the object bent the light, Andrew Gould of Ohio State University in Columbus and colleagues have now found that it is a brown dwarf – a “failed star” with too little mass to sustain the nuclear reactions that power stars.

Current estimates of how common brown dwarfs are suggest this finding is improbable – so …