The supernova SN1987A certainly produced some heavy...

The supernova SN1987A certainly produced some heavy elements. Compared to the energy released in fusing $56{ }^{1} \mathrm{H}$ atoms into one ${ }^{56} \mathrm{Fe}$ atom starting from the protonproton cycle, how much energy would be required to fuse two ${ }^{56} \mathrm{Fe}$ atoms into one ${ }^{112} \mathrm{Cd}$ atom?

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Key Concepts

Binding Energy per Nucleon

This concept refers to the energy that holds a nucleus together, divided by the number of nucleons it contains. It reaches a maximum around the iron peak, which means that fusing light elements up to iron releases energy because the products are more tightly bound than the reactants; however, fusing elements heavier than iron requires an input of energy since their binding energy per nucleon decreases.

Nuclear Reaction Q-value

The Q-value is the net change in energy during a nuclear reaction, determined by the difference in total binding energy between the initial and final nuclei. A positive Q-value indicates that energy is released (exothermic), while a negative Q-value indicates that energy must be supplied (endothermic). This concept is crucial when comparing the energy from fusing hydrogen into iron versus fusing iron into heavier elements like cadmium.

Stellar Nucleosynthesis

This is the process by which stars build new elements through nuclear reactions. In the cores of stars, fusion processes efficiently produce energy when lighter elements are combined into heavier ones up to iron. Beyond iron, further fusion is not energetically favorable and typically occurs in extreme environments, such as supernovae, where the required energy is available to overcome the endothermic barrier.

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