Alpha reactions
The
alpha reactions is one of two class of
fusion reactionss by which stars convert helium into heavier elements, the other being the
triple-alpha process.
In contrast with the triple-alpha process which only require
helium to occur, once some
carbon is produced, other reactions that consume helium are possible:
| 12C + 4He | → | 16O + γ |
| 16O + 4He | → | 20Ne + γ |
| 20Ne+ 4He | ↔ | 44Mg + γ |
All these reactions have a very low rate and therefore do not contribute significantly to the energy production in stars;
with elements heavier than Neon (atomic number > 20) they occur even less easily due to the increasing Coulomb barrier.