What is the smallest known star in the Universe?

In 2017, an international team of astronomers announced the discovery of a socalled red dwarf star that’s so small it barely functions as a star. Code-named EBLM J0555-57Ab and lying some 600 light-years away, it’s similar in size to the planet Saturn. It has just enough mass to maintain the conditions needed to fuse together nuclei of hydrogen – the power source of stars like the Sun. Any smaller, and it would have become a brown dwarf – a ‘failed star’.