Expert: Jayendra Upadhye - 4/12/2007

Question
hi im wondering how iron is specifically produced in the universe. i kno that type II supernova only eject small quantities of iron and i understand that type Ia supernova are one of the main processes of iron production but could you explain exactly how this production occurs? many thanks

Answer
Daniel, sorry for the late answer.
Only a real research guy can answer your question if you want an answer regarding the nuclear reactions etc.
It would be enough from my side to say that iron is produced in those stars that have enough gravitational capital to expend when the time comes, in the form of greater mass, to crush the core enough to start and sustain iron formation by fusion.

Iron formation being an endotheric reaction (consumes energy instead of yielding a surplus), quickly cools the core! thus it actually quenches the stellar fires raging in the core! And accelerates core implosion.

once it starts, the core starts to shrink, and gravity keeps the relentless pressure on, leading to continued iron formation and continued core cooling!

It is a runaway process.

Implosion quickly follows. The rest is completed by the supernova that comes from total core implosion to nutron star formation and the rebound of other material falling inwards. The shock of the rebound triggers the supernova where not only iron, but all trans iron elements are formed.

hope that answers your question.
Jayen