New research from the University of Michigan shows that there may be an upper limit to the size of a star, somewhere around 120 to 200 times bigger than our sun. The sun is the closest star to Earth and therefore looks very big to us, but compared to other stars in the Milky Way, it’s considered a low-mass star. Knowing that there may be a limit to a star’s mass answers a fundamental question, but raises a raft of other issues about what limits their mass, said Sally Oey, assistant professor of astronomy.