In stars, the fusion of H and He initiates a whole series of nuclear fusion reactions which continue up to iron, or more precisely to Fe-56. At this point the spontaneous formation of heavier elements stops, since it is no longer energetically favourable to fuse nuclei together. This can be appreciated from the Binding Energy (BE)/nucleon curve shown in Figure 2. Stable nuclei can be spontaneously formed only when there is a gain in BE in the fusion process, which is the case for the fusion of lighter nuclei up to the maximum of Fe-56, the most stable nucleus. Fusion reactions beyond Fe would require energy and hence the spontaneous nuclear fusion process stops. Other processes then have to be implemented to generate the heavier eleme