| p-process | nucleosynthetic reaction | The name of the hypothetical nucleosynthetic process thought to be responsible for the synthesis of the rare heavy proton-rich nuclei which are bypassed by the r-process and s-processes. It is manifestly less efficient (and therefore rarer) than the s- or r-process, since protons must overcome the Coulomb barrier, and may in fact work as a secondary process on the r-process and s-process nuclei. It seems to involve primarily (p, γ) reactions below cerium (where neutron separation energies are high) and the (γ, n) reactions above cerium (where neutron separation energies are low). The p-process is assumed to occur in supernova envelopes at a temperature greater than about 109 K and at densities less than about 104 g cm-3. |
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