Why Does Iron Trigger a Supernova in Stars?

[koustov]

in discovery they were showing that at last stage of a star it creates witihn itself different metals...bt wen it creates iron its time for its death...why iron makes the star burst into supernova?/any one please tell me...

 

[nismaratwork]

in discovery they were showing that at last stage of a star it creates witihn itself different metals...bt wen it creates iron its time for its death...why iron makes the star burst into supernova?/any one please tell me...

Iron is the last element (probably, maybe some calcium too) that is created in stellar fusion. It is a sign that the star has exhausted its nuclear fuel, and without the constant activity of fusion to provide a force acting against gravity, implosion occurs. Thus Kaboom, thus Supernova. It is less of a cause, and more of a death-knell.

 

[koustov]

but why iron is like that?what does iron do?whats special about it??please tell me...

 

[Janus]

Iron cannot fuse without a net input of energy. Up until iron there is a net release of energy by fusion that helps counteract the weight of the star's gasses pushing inward. Once iron forms it just starts to build up in the center of the star, with all the fusion taking place in the layers just above it. Eventually, the iron core becomes so massive that its own atomic bounds can no longer support the weight. It suddenly collapses into a much denser and smaller ball of matter.

This leaves a hollow for the upper layers to fall into. This sudden infall is energetic enough when it hits the new smaller core to cause all the remaining star to undergo fusion at once, causing the supernova.

 

[BillSaltLake]

Because they said iron is "poison" to a star, you may have gotten the impression from that TV show that if someone dumped a little iron into an old star, it would explode. This is not the case. The production of iron in the core is a symptom that the star is about to explode because it's running out of fusile material.

 

[koustov]

thank you...i hav got my answers...

 

[inflector]

If you want a little more information explaining why Iron is the element that ends the fusion process in stars, you might find this link helpful:

http://www.einstein-online.info/spotlights/binding_energy/

It all comes down to a concept known as binding energy which the link explains very well.

- Curtis