Answer;
-Explosion of supernovas
Atoms heavier than iron are generally produced by the process of explosion of supernovas.
Explanation;
Many elements heavier than iron or all of the post-iron elements are formed supernova explosions. The amount of energy released during a supernova explosion is so high that the freed energy and copious free neutrons streaming from the collapsing core result into massive fusion reactions, long past the formation of iron.
For elements lighter than iron on the periodic table, nuclear fusion releases energy while fission consumes it. Chemical elements up to the iron peak are produced in ordinary stellar nucleosynthesis. Heavier elements are produced only during supernova nucleosynthesis.
