Our galaxy could have 100 billion brown dwarfs or more, according to a new research by an international team of astronomers.
Brown dwarfs are objects intermediate in mass between stars and planets and are natural byproducts of processes that primarily lead to the formation of stars and planets.
The survey of dense star clusters where brown dwarfs are abundant, presented at the National Astronomy Meeting at the University of Hull, found thousands of brown dwarfs in star clusters relatively close to the Sun.
"We've found a lot of brown dwarfs in these clusters. And whatever the cluster type, the brown dwarfs are really common. Our work suggests there are a huge number of brown dwarfs out there," said Aleks Scholz from the University of St Andrews, in Scotland.
The survey looked at the star cluster 'NGC 1333', some 1,000 light years away in the constellation of Perseus, and found about half as many brown dwarfs as stars.
The team later turned to a more distant star cluster, 'RCW 38', which is 5,500 light years away in the constellation of Vela. This has a high density of more massive stars, and very different conditions to other clusters.
The researchers found just as many brown dwarfs in 'RCW 38' and realised that the environment where the stars form has only a small effect on how brown dwarfs form.
The researchers estimate that within just our galaxy there is a minimum of between 25 and 100 billion brown dwarfs.