![]() Many of the supernova remnants will lead to the formation of neutron stars, which can produce the greatest abundances of the heaviest elements of all by colliding and merging. The final stage of fusion is typically silicon-burning, producing iron and iron-like elements in the core for only a brief while before a supernova ensues. The anatomy of a very massive star throughout its life, culminating in a Type II Supernova when the. All three of these are more than capable of ending any life that's managed to survive on an orbiting planet up to that point, but the big question of how we'd all die if the Sun went supernova depends on the answer to one question: who gets there first? That energy goes into a mix of radiation (photons), the kinetic energy of the material in the now-exploding stellar material, and neutrinos. The fusion reaction itself lasts for only around 10 seconds, liberating about 10 44 Joules of energy, or the mass-equivalent (via Einstein's E = mc 2) of about 10 27 kg: as much as you'd release by transforming two Saturns into pure energy. ![]() A runaway fusion reaction occurs, producing what's basically one giant atomic nucleus made of neutrons in the star's core, while the outer layers have a tremendous amount of energy injected into them. This is where the core-collapse supernova happens. NASA/CXC/M.Weiss X-ray: NASA/CXC/GSFC/U.Hwang & J.Laming We do not know whether all core-collapse supernovae follow the same pathway or not. (Silicon-burning is where iron, nickel, and cobalt form in the core.) A Chandra image (right) of the Cassiopeia A supernova remnant today shows elements like Iron (in blue), sulphur (green), and magnesium (red). Instead, nothing there is capable of resisting gravitational collapse, and the core implodes.Īrtist's illustration (left) of the interior of a massive star in the final stages, pre-supernova. The elements that are produced from silicon fusion - elements like cobalt, nickel and iron - are more stable than the heavier elements that they'd conceivably fuse into. Again, the pressure drops, but this time there's nowhere to go. In that final phase of silicon-burning, core temperatures can reach ~3 billion K, some 200 times the hottest temperatures currently found at the center of the Sun.Īnd then the critical moment occurs: the core runs out of silicon. ![]() When carbon becomes scarce in the core, it again contracts and heats up, leading to neon fusion (which lasts about a year), followed by oxygen fusion (lasting for a few months), and then silicon fusion (which lasts less than a day). LeeĬarbon fusion can produce elements such as oxygen, neon, and magnesium, but only takes hundreds of years to complete. When the star explodes, the vast majority of the outer layers absorb neutrons rapidly, climbing the periodic table, and also get expelled back into the Universe where they participate in the next generation of star and planet formation. concentrated toward the center of the star. As it nears the end of its evolution, heavy elements produced by nuclear fusion inside the star are. ![]()
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