This is NGC 1818,a youthful, glittering clusterof 20,000 stars residing in th LargeMagellanic Cloud, 180,000 light-years away.Pick a star. Any star Astronomersmight pick the unassuming bluish-white one (circled) whic appearsto be a hot newly formed white dwarf star.What makes it so interesting?The standard astronomical wisdomsuggests that stars over 5 times as massive as thesun rapidly exhausttheir nuclear fuel and end their lives in a spectacula supernova explosion.With less than this critical massthey evolve into red giants, pass through a relatively peaceful planetary nebula phase,and calmly fade away a white dwarf stars like this one.Except that as a member of the NGC 1818 cluster,this new white dwarf would have evolved fro a redgiant star over 7.6 times as massive as thesun -- which should have exploded Its discoverywill likely force astronomers to revise thelimiting mass estimate for supernovae upward.
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