Why can't Iron be fused in the most heaviest stars?
We all know as soon a supergiant star starts to form iron it will not fuse that iron into any heavier element. Question is, why not? If you take the most heaviest stars, stars that are like 150-200 times the mass of our Sun (and consider Betelgeuse with only 15 solar mass will go Supernova), why won't such a star fuse iron into a heavier element? Iron is only number 26 on the periodic table. Surely if the pressure and heat is strong enough denser elements could be formed, like Gold, Uranium etc. That stuff will form when a supernova occurs, so there is no mechanism that prevents the actual fusing of iron.
- CliveLv 76 months agoFavorite Answer
Because when lighter elements fuse, that releases energy and fusion can continue. But to create atoms heavier than iron needs energy putting IN, so this can't go on for long. The star will run out of energy to put into the fusion reactions, those have to stop and it collapses.
This causes the temperature and pressure to go sky-high and yes, in a fraction of a second while that lasts, heavier elements can be and are made by fusion. But only in that fraction of a second before the star blows itself apart as a supernova. Which is why all heavier elements are relatively rare.
- WhoLv 75 months ago
they cant create the temperatures and pressures necessary to create atoms of elements heavier than iron
(you cant create atoms of elements heavier than the one you started with by fission "billrussell"
you can only create them by fusion)
- RaymondLv 75 months ago
It can. However, it costs more energy to fuse iron atoms than the energy you get out of it.
When a star collapses (once its core is mostly iron), some of that iron fuses and gets thrown out as heavier elements. However, that is because the required energy comes from the collapse itself. This fusion definitely cannot support the star which goes supernova. Whatever remains in the core (mostly iron) gets fused into a neutron star or... into whatever forms a black hole.
A neutron star still has (we think) an "atmosphere" of solid, crystalized iron a few centimeters thick.
- Ronald 7Lv 75 months ago
Iron as an Element just doesn't Fuse
Its isotopes are just too Stable
- How do you think about the answers? You can sign in to vote the answer.
- SharonLv 65 months ago
it is due to the "curve of binding energy", i.e. fusion of lighter elements creates energy, while fission of heavier elements creates energy. Iron sits in the middle where either requires more energy than is created.
- D gLv 76 months ago
the amount of energy needed exceeds that which most stars can withstand .. usually the supernova happens before the star can reach the energy levels of the iron I think.. plus Iron is a very stable element
- Jeffrey KLv 66 months ago
Energy is given off when light elements fuse. But in order to fuse iron into heavier elements, you must put energy in. This would not make a star shine, it would take energy away from it.
In a supernova, there is lots of energy around to put into atoms to make them fuse into heavier elements.
- 6 months ago
it can and the instant the massive stars start fusing Iron they blow up
- billrussell42Lv 76 months ago
iron is at the valley of nuclear energy. elements lighter can release energy by fusing. Those heaver by fission.
- 6 months ago
Because - it *takes* energy to fuse Iron... Iron *does* fuse; but when it does, it consumes energy in the process - and no star can "live" while needing energy. It's only in the energy of the intense collapse of the star do the heavier elements form.