how the heavier elements such as iron are produced in astrophysical processes?

Answer 1

Look up stellar nucleosynthesis.

John W. corrects Linda, and his answer is indeed better. But to wax pedantic, there are two elements heavier than iron that are produced through regular stellar fusion. They both have short half lives, so the ultimate result is that no element heavier than iron is produced through standard stellar nucleosynthesis.

The elements heavier than iron are produced via supernova. The natural distribution of the elements in our universe tends to confirm this. Elements heavier than iron tend to be much rarer. Iron is quite abundant, as is aluminum, oxygen, silicon, carbon, nitrogen, and other common byproducts of fusion.

Lead tends to be more common than gold because it is the end product of a long fission sequence. Fissionable isotopes tend to be rarer because they transmute into other, lighter elements.

Answer 2

The heavier elements, like iron, lead, gold, etc.,. are produced only in stars that explode at the end of their lives, an event called a 'supernova.' It's only during a supernova event that enough energy is generated to fuse the other elements left in the star into much heavier ones. Also during the supernova, these heavier elements are blasted into interstellar space where some of them at some time in the distant future will combine with other elements and form new stars, planets, and even people. The heavier elements in our bodies was "coooked up" untold billions of years ago when some ancient red giant star blew itself apart.

Answer 3

It's part of the life-cycle of a star. Main-sequence stars, like our Sun, are fueled by hydrogen. When the hydrogen is depleted, a nova/supernova causes a change in the star, after which helium, created from the hydrogen prior to the nova, becomes the main fuel source. This changes the helium into heavier elements. A second eruption occurs after the helium fuel is depleted. Several more stages finally bring the star to its final stage, at which time, the core is now iron and other heavy elements. During the star's lifetime, helium, carbon, oxygen, iron, and other elements are created through fusion of the core atoms.

Answer 4

Stars fuse light elements into heavier ones - its that fusion that powers the stars.
But iron and heavier elements are not produced in ordinary stars like our sun because fusing iron requires an input of energy, it doesn't create energy for the stars.
But in a supernova explosion, there is so much extra energy suddenly around that supernova can create heavy elements for a short time, before the final explosion diffuses those elements into the interstellar medium.

Answer 5

All the above.