An international team of astronomers and researchers led by the University of Cambridge found that the first stars near the center of the Milky Way could have died in spectacular "hypernovae," stellar explosions that released ten times more energy than a supernova.This is significant because the early explosions would have expelled much of the metals that make younger, more metal-rich stars, such as ours, to further reaches of the galaxy.
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"This would make it one of the most energetic things in the Universe, and very different from the kinds of stellar explosions we see today," according to a press release.The researchers published their observations in Nature on some stars found near the center of the Milky Way, which have existed for billions of years, had low metal concentrations. The metal composition of these stars is particularly important; astronomers use it to classify different populations of stars that could have been formed during different points of the universe's lifespan.Because metals can only be fused using the energy of a supernova, stars containing heavier metals must be formed from the dust of numerous past supernova fusions. Thus, metal-rich stars are likely to be younger stars, and metal-poor ones are generally older, or are located in less metal-dense parts of the universe.Population III stars, as astronomers call them, are so metal-poor that it's likely they were formed shortly after the Big Bang. The stars have few metals "recycled" from past stellar cycles.When the University of Cambridge observed that those metal-poor stars must have existed near the center of the galaxy for billions of years, rather than just passing through from metal-poor areas, they also found chemical signatures that suggest that those stars must have been formed through a hypernova, "an extremely energetic kind of supernova releasing ten times the kinetic energy of regular core-collapse supernovae."