Sources
Help build the largest human-edited directory on the web.
Submit a site - Become an editor
Wikipedia. Licensed under the GNU Free Documentation License.
Are you an expert in this subject? Join the discussion and share your knowledge at Wikipedia.org.
P-process
From Wikipedia, the free encyclopedia
| Nuclear processes |
|---|
Radioactive decay processes
|
The p process is a proton capture process. It is believed that photodisintegration reactions are responsible for the production of the proton-rich p-isotopes with masses A>100. The relevant reactions are (gamma,n)- and (gamma,alpha)-reactions. The temperature during a supernova explosion reaches up to 2×109 to 3×109 K. The black body radiation produces a photon bath that can disintegrate the seed nuclei from the s-process and r-process. This is the reason why the p-process is sometimes called gamma-process.
The p-process contribution to isotopic abundances of elements that can also be produced in the s-process or r-process is usually very small. However there are p-only isotopes that cannot be produced in the s- or r-process (e.g. 190Pt or 168Yb). These isotopes have very small abundances compared to neighbour nuclei.
Sometimes the term p-process includes also the rp-process (rapid proton capture process). The astrophysical scenario for this process is still not firmly established but it is believed that a neutron star in a binary system which is accreting mass from a main sequence star could be one possible scenario. During X-ray bursts the temperature and the proton density are high enough to start proton capture reactions and proton rich elements up to mass A=100 can be produced.