Undergrad Do Stars Fuse Elements Heavier Than Iron Before Imploding?

[LightningInAJar]

TL;DR

Anything beyond iron?

I know black holes are stars that fuse together elements until they reach iron which doesn't radiate energy to counterbalance the gravity, but do any stars fuse elements heavier than iron that would once again give off energy prior to it imploding?

By the way, why doesn't iron creation create radiation?

 

[Orodruin]

Summary:: Anything beyond iron?

I know black holes are stars that fuse together elements until they reach iron which doesn't radiate energy to counterbalance the gravity

This is incorrect. A black hole is a region of spacetime from which light cannot escape.

Regarding fusing of elements: Iron has the highest binding energy per nucleon. It would not be energetically favorable to fusion it to heavier elements.

 

[Ibix]

As Orodruin says, a black hole is not just a star that's stopped fusing. That leads to a (super)nova and some larger stars collapse into black holes, but a black hole is very different from a star.

All sorts of heavy elements get produced in supernovae. I'm sure they get produced in tiny quantities in during normal operation, but it's an energy absorber not a producer so the process isn't self-sustaining. That's why you don't see iron-burning stars - it's the fusion equivalent of trying to light ashes.

As to why iron doesn't produce energy, the binding energy per nucleon changes as the atomic mass rises. It first increases, meaning that one helium atom needs slightly more energy to separate it into four nucleons than two deuterium atoms do. So two deuterium atoms combining into one helium leaves a bit of energy over.

But that stops at iron, and then the trend reverses. Very heavy elements need less energy to separate into components than smaller ones, so combining smaller atoms costs energy. Splitting large atoms into smaller ones (down to iron) releases energy - which is nuclear fission.

The underlying reason for the differences in binding energy is the balance between the strong force holding the nucleus together and increasing amounts of electrostatic repulsion between the increasing number of protons.

 

[Vanadium 50]

Summary:: Anything beyond iron?

I know black holes are stars that fuse together elements until they reach iron which doesn't radiate energy to counterbalance the gravity

You have a very bad habit of starting threads with "I know that" followed by something totally false. These are bad starts. Please stop this.

 

[Nugatory]

Summary:: Anything beyond iron?

By the way, why doesn't iron creation create radiation?

It does in some cases, for example the decay of Ni-56 to Fe-56.

Before you can understand the nuclear reactions involved in stellar evolution and collapse you will need a better understanding of the most important nuclear processes: fusion, fission, alpha and beta decay - you might start by searching for "binding energy curve" and "decay chain".

As this thread is based on a misunderstanding that has been addressed, it is closed.