One of the biggest mysteries in astronomy, how stars blow up in supernova explosions, finally is being unraveled with the help of NASA's Nuclear Spectroscopic Telescope Array (NuSTAR). The high-energy X-ray observatory has created the first map of radioactive material in a supernova remnant. The results, from a remnant named Cassiopeia A (Cas A), reveal how shock waves likely rip apart massive dying stars.
Cas A was created when a massive star blew up as a supernova, leaving a dense stellar corpse and its ejected remains. The light from the explosion reached Earth a few hundred years ago, so we are seeing the stellar remnant when it was fresh and young.
Supernovas seed the universe with many elements, including the gold in jewelry, the calcium in bones and the iron in blood. While small stars like our sun die less violent deaths, stars at least eight times as massive as our sun blow up in supernova explosions. The high temperatures and particles created in the blast fuse light elements together to create heavier elements.
NuSTAR is the first telescope capable of producing maps of radioactive elements in supernova remnants. In this case, the element is titanium-44, which has an unstable nucleus produced at the heart of the exploding star. The NuSTAR map of Cas A shows the titanium concentrated in clumps at the remnant's center and points to a possible solution to the mystery of how the star met its demise.
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