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I found out that iron is the death element for stars, but I couldn't find why can anyone knowledgeable on stars explain why iron causes the star to die?

peterh
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Little Bowsette
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    by simple research, https://futurism.com/what-happens-when-stars-produce-iron – seVenVo1d Jan 22 '19 at 18:53
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    Related, but it doesn't exactly answer your question: https://physics.stackexchange.com/q/80256/ Also see https://physics.stackexchange.com/q/79355/ and https://physics.stackexchange.com/q/215769/ and from our sister site https://astronomy.stackexchange.com/q/2231/ – PM 2Ring Jan 22 '19 at 18:57
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    I would like it if people that down-vote explain rather than just annoy me by not helping me improve it – Little Bowsette Jan 25 '19 at 20:04

2 Answers2

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This is the binding energy of some elements as a function of their number of nucleons

enter image description here

Since fusion leads to a higher number of nucleons, what a star does is to progressively move from left to right on this plot.

So if you start on the left, say H, you merge two, and the result has a larger binding energy, so energy is released. But that behavior is broken when you reach Fe$^{56}$, at that point, you need extra energy. Since the star cannot produce it, it stops fusing material, and it dies off

caverac
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    @Luna Glad it was of help – caverac Jan 25 '19 at 20:06
  • @Luna It can be frustrating, sorry you had a bad experience with your first post – caverac Jan 25 '19 at 20:12
  • my bet is they down-voted thinking this person is crazy – Little Bowsette Jan 25 '19 at 20:13
  • @Luna The site has a strong policy against homework-type questions which, in my humble opinion, ends up being a bit counterproductive. But ... it is what it is. Maybe that's the reason some users decided to downvote your post (just guessing), I just hope this doesn't discourage you from keep posting your questions as it really helps growing the community – caverac Jan 25 '19 at 21:05
  • except the first question was not homework type or my last one plus I am in earth science not physics so homework type is: why is magnetite magnetic, in my case – Little Bowsette Jan 25 '19 at 21:08
  • it was on topic it was closed as was unclear – Little Bowsette Jan 25 '19 at 21:08
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    @Luna I understand that, that's what I mean by counterproductive. Because some users prefer just to jump the guns and down-vote, or mark as off-topic, instead of taking the time to see the value in the question. – caverac Jan 25 '19 at 21:11
  • wow, have you seen my rep has been skyrocketing? – Little Bowsette Jan 30 '19 at 19:09
  • This is not the whole story. For example, if you add an alpha particle to a 56Ni nucleus, then this produces heat. Neither does the fact that fusion ceases cause the star to "die", unless you also regard a white dwarf as "dead". If "death" here refers to core-collapse and possibly a supernova, then the causes are different. – ProfRob Sep 12 '20 at 09:23
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A star "dies" when the fusion stops. 56Fe is the most stable nucleus that exists so it is the ultimate fusion product. Any nucleons contained in it no longer contribute to the energy production.

my2cts
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