How big are stars? They range in size from giants hundreds of times the size of our sun to tiddlers much smaller than our sun. A team of astronomers at the University of Cambridge recently announced the discovery of the smallest star ever to be detected. EBLM J0555-57Ab is roughly 600 light-years away and is about the size of the planet Saturn. As a reference point you can fit about 1600 Saturns inside our Sun, so EBLM J0555-57Ab is really a very small star indeed.