High-mass stars with degenerate neutron cores

The present paper investigates whether a star more massive than about 12 solar masses and containing a degenerate neutron core can produce its required luminosity by nuclear burning in a nondegenerate region a few tens of kilometers thick, just above the neutron core. Two related models of rp burning (rapid, direct addition of protons onto nuclei) in such a star are constructed. It is inferred from these models that the re-process can produce the required luminosity, and they make clear the basic physical and chemical structure of a star supported by the process. It is proposed that such a star is distinguishable from a red supergiant with a degenerate electron core by the presence of spectral lines of hydrides of some of the rp reaction products. The lifetime of the star in its re-burning phase is argued to be about the same as the lifetime of a normal red supergiant of the same mass with a degenerate electron core.