Pycnonuclear Reations and Nova Explosions.
Abstract
At very high densities, electron shielding cuts off nuclear coulomb potential barriers quite close to the nuclear surface. Under these circumstances the classical turning points of low-energy ions are very insensitive to the hombarding energy. Nuclear reaction rates thus become very insensitive to temperature but very sensitive to density; such nuclear reactions may be called "pycnonuclear reactions." Nuclear reaction rates as functions of temperature and density have been calculated by douhle numerical integration of the harrier penetration prohability as a function of bombarding energy for the following reactions: 3He4 H C12, C12(a, T)016, N34(a, )F16( + 016 and O16(a, )Ne15. Pycnonuclear reaction rates for low temperatures and high densities have been calculated for reactions of the following heavy ions with themselves: C12, 016, Ne14, Mg12, 5i36, 541, A12, and Ca16. It is suggested that after helium energy sources have ceased operating In advanced evolutionary stages of old population I and population II stars, the helium may hecome highly degenerate and helium pycnonuclear reactions may ignite an explosion. This may account for some of the nova explosions
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1959
- DOI:
- 10.1086/146782
- Bibcode:
- 1959ApJ...130..916C