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sciguy52 t1_jdfdakq wrote

Reply to comment by CrustalTrudger in Does the metal in the solid core of a rocky planet have any special properties? by VillagerNo4

I don't know a lot about this so maybe a dumb question. Did iron make up so much of the solar nebula that we ended up with so much iron in the core? I know H and He were in most abundance but sort of assumed the next levels of abundance would be the next elements in the periodic table.

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notimeforniceties t1_jdfzfu5 wrote

Someone else can probably explain this properly, but I believe the fusion reaction inside the Sun ends up leaving it as all Iron. Something about the fusion reaction past a certain point can't produce elements higher than Iron on the period table.

Edit: https://www.ck12.org/flexi/chemistry/nuclear-fusion-in-chemistry/why-do-nuclear-fusion-reactions-stop-once-nickel-and-iron-are-formed-in-the-core-of-stars/

> When very massive stars leave the main sequence, they first become red supergiants and then end their life cycles in with a bang. Unlike a red giant, when all the helium in a red supergiant is gone, fusion continues. Lighter atoms fuse into heavier atoms up to iron atoms. Creating elements heavier than iron through fusion uses more energy than it produces so stars do not ordinarily form any heavier elements.

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DaddyCatALSO t1_jdg3k8i wrote

Eventually; iron is the sink for fusion of lighter and decay of heavier. But "dead" stars are often not mostly iron.

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