 The first stars to form after the Big Bang may have been larger , up to 300 M ☉ , due to the complete absence of elements heavier than lithium in their composition . This generation of <unk> population III stars is likely to have existed in the very early universe ( i.e. , they are observed to have a high <unk> ) , and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life . In June 2015 , astronomers reported evidence for Population III stars in the Cosmos <unk> 7 galaxy at <unk> = 6 @.@ 60 . 
