Methods

In order to model GR instability supernovae, we first perform evolutionary simulations with a post Newtonian stellar evolution code HOSHI, both for metal free and metal enriched progenitors. This code includes a small nuclear network and neutrino cooling. We evolve these simulations to the general relativistic radial instability. We locate the instability by performing a normal mode analysis of the radial perturbations of the star in general relativity by linearizing the equation of motion. Next, when the star becomes unstable according to the general relativistic stability analysis, we simulate the dynamics of the explosion or collapse to a black hole by transporting the model to a general relativistic Lagrangian hydrodynamics code with a nuclear network. We use nuclear networks of different sizes depending on the progenitor, but the two main explosion mechanisms for these stars are the explosive alpha process and the CNO cycle and rapid proton capture process. Finally, if the model explodes, we compute the nucleosynthetic ejecta using post processing of the hydrodynamical trajectories. We also calculate the light-curve of the explosion using a radiation hydrodynamics code.