How were the heavy elements from iron to uranium made?

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Age of the Earth and the star that preceded the Sun

References: http://www.phy.anl.gov/accelerator_rd/index.html

Review of proposed Tech: http://www.annualreviews.org/doi/abs/10.1146/annurev.nucl.55.090704.151604

score 4 · Accepted Answer · answered Jun 12 '12 at 20:56

The two main contributions are thought to be from the s-process and the r-process, which are both neutron capture processes that are differentiated by their speed relative beta-decay of neutron rich isotopes.

Both are end-of-stellar-life processes with the S-process probably happening in the giant stages of very heavy stars and the r-process probably happening in core-collapse supernovas.

score 2 · Answer 2 · answered Jun 12 '12 at 05:22

Unlike light elements, which release energy during fusion, elements heavier than iron require energy for their creation. This happens because the nuclear binding energy is at its maximum at iron. Hence lighter elements were made in ordinary stars, using fusion. However, heavier elements were made in supernovas, as huge amounts of extra energy are released during the explosion, some of which is used to force heavy nuclei together and create heavier elements.

How were the heavy elements from iron to uranium made?

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