  The cross section of the radiative proton capture reaction on the drip line
nucleus 12N was investigated using the Asymptotic Normalization Coefficient
(ANC) method. We have used the 14N(12N,13O)13C proton transfer reaction at 12
MeV/nucleon to extract the ANC for 13O -> 12N + p and calculate from it the
direct component of the astrophysical S factor of the 12N(p,gamma)13O reaction.
The optical potentials used and the DWBA analysis of the proton transfer
reaction are discussed. For the entrance channel, the optical potential was
inferred from an elastic scattering measurement carried out at the same time
with the transfer measurement. From the transfer, we determined the square of
the ANC, C^2(13Og.s.) = 2.53 +/- 0.30 fm-1, and hence a value of 0.33(4) keVb
was obtained for the direct astrophysical S factor at zero energy. Constructive
interference at low energies between the direct and resonant captures leads to
an enhancement of Stotal(0) = 0.42(5) keVb. The 12N(p,gamma)13O reaction was
investigated in relation to the evolution of hydrogen-rich massive Population
III stars, for the role that it may play in the hot pp-chain nuclear burning
processes, possibly occurring in such objects.
