Rp-process

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Nuclear processes

Radioactive decay processes Alpha decay Beta decay Cluster decay Double beta decay Double electron capture Electron capture Gamma radiation Internal conversion Isomeric transition Neutron emission Positron emission Proton emission Spontaneous fission Nucleosynthesis Nuclear fusion Proton-proton chain reaction CNO cycle Triple alpha process Carbon burning process Neon burning process Oxygen burning process Silicon burning process Neutron capture The R-process The S-process Proton capture: The P-process The Rp-process Spallation

The rp process (rapid proton capture process) consists of consecutive proton captures onto seed nuclei to produce heavier elements. It is a nucleosynthesis process and, along with the s process and the r process, is responsible for the generation of many of the heavy elements present in the universe. The end point of the rp process (the highest mass elemtent it can create) is not yet well established but recent research has indicated that in neutron stars it cannot progress beyond tellurium.^[1]

[edit] Conditions

The process has to occur in very high temperature environments so that the protons can overcome the large coulomb barrier for charged particle reactions. A hydrogen rich environment is also a prerequisite due to the large proton flux needed. The seed nuclei needed for this process to occur are thought to be formed during breakout reactions from the hot CNO cycle.

[edit] Possible sites

Sites suggested for the rp process include white dwarf or neutron star binary systems. In these systems a star (often a red giant) is feeding hydrogen rich material onto its white dwarf or neutron star companion. This causes an increase in temperature of the white dwarf or neutron star creating the conditions necessary for the rp process.

[edit] References

1. ^ Schatz, H., A. Aprahamian, V. Barnard, L. Bildsten, A. Cumming, M. Ouellette, T. Rauscher, F.-K. Thielemann, and M. Wiescher (April 2001). "End Point of the rp Process on Accreting Neutron Stars". Physical Review Letters 86 (16): 3471–3474. DOI:10.1103/PhysRevLett.86.3471. Retrieved on 2006-08-24.