Free Astronomy Magazine November-December 2022

14 NOVEMBER-DECEMBER 2022 ASTRO PUBLISHING By analyzing one of the most distant known quasars using the Gemini North telescope, one of the two identical telescopes that make up the International Gemini Observa- tory, operated by NSF’s NOIRLab, as- tronomers now think they have identified the remnant material of the explosion of a first-generation star. Using an innovative method to deduce the chemical elements con- tained in the clouds surrounding the quasar, they noticed a highly unusual composition — the material con- tained over 10 times more iron than magnesium compared to the ratio of these elements found in our Sun. The scientists believe that the most likely explanation for this striking feature is that the material was left behind by a first-generation star that exploded as a pair-instability su- pernova. These remarkably power- ful versions of supernova explosions have never been witnessed, but are theorized to be the end of life for gigantic stars with masses between 150 and 250 times that of the Sun. by NOIRLab Charles Blue Potential first traces of the Universe’s earliest stars T he very first stars likely formed when the Universe was only 100 million years old, less than one percent its current age. These first stars — known as Population III — were so titanically massive that when they ended their lives as su- pernovae they tore themselves apart, seeding interstellar space with a distinctive blend of heavy el- ements. Despite decades of diligent searching by astronomers, however, there has been no direct evidence of these primordial stars, until now.