Making carbon in stars

The triple alpha (3α) process plays an important role in the production of 12C in stars. Its rate is known with an accuracy of about 12%. We examine the corresponding uncertainties introduced in the description of pre-supernova stars, of nucleosynthesis in a core-collapse SN explosion, and of the production of 12C during the third dredge-up in asymptotic giant branch (AGB) stars. For the AGB case we consider also the effects of uncertainties in the 14N(p, γ)15O rate. We conclude that the present accuracy of the 3α rate is inadequate and describe new experiments that will lead to a more accurate value.