In 2005, studies conducted by NASA using the Hubble Space Telescope showed astronomers that stars have an upper limit of about 150 times the mass of the Sun. The Hubble telescope was used to measure stars in the Arches Cluster, which is the densest group of stars found in the Milky Way and about 25,000 light years away.
Expecting to find as many as 30 stars with masses up to 1,000 times the Sun’s mass, astronomers were surprised to find that the largest ones were only about 130 solar masses instead. One theory is that the intense radiation from large stars blows them apart; if a star is 100 times the solar mass, that means it burns about a million times brighter than the Sun.
However, star R136a1 was found in 2010 in the R136 star cluster 165,000 light years away, which was 300 times the mass and 10 million times brighter than our Sun, so while we’re still unsure exactly what the upper limit is, there’s little doubt that there is one.
Answered by Shanna Freeman