Binding energy Silicon-burning process

curve of binding energy

the graph above shows binding energy per nucleon of various elements. can seen, light elements such hydrogen release large amounts of energy (a big increase in binding energy) when combined form heavier elements—the process of fusion. conversely, heavy elements such uranium release energy when broken lighter elements—the process of nuclear fission. in stars, rapid nucleosynthesis proceeds adding helium nuclei (alpha particles) heavier nuclei. although nuclei 58 (iron-58) , 62 (nickel-62) nucleons have highest binding energy per nucleon, converting nickel-56 (14 alphas) next element, zinc-60 (15 alphas), decrease in binding energy per nucleon , consumes energy rather releasing any. accordingly, nickel-56 last fusion product produced in core of high-mass star. decay of nickel-56 explains large amount of iron-56 seen in metallic meteorites , cores of rocky planets.