Uncovering carbon burning in stars

Carbon burning takes place in stars at deep sub-Coulomb energies through the C-12(C-12,alpha)Ne-20 and C-12(C-12,p)Na-23 reactions. Here we report the first measurement of these reactions at the relevant energies via the Trojan Horse Method off the deuteron in N-14. In particular, the C-12 + C-12 fusion has been measured from E-c.m.=2.7 MeV down to 0.8 MeV. This range of energies is relevant for several astrophysical scenarios, from superburst ignition to quiescent burning. The astrophysical S(E) factors reveal several resonances, which are responsible for a very large increase of the reaction rate at the relevant temperatures.