Revisiting Impacts of Nuclear Burning for Reviving Weak Shocks in   Neutrino-Driven Supernovae
  We revisit potential impacts of nuclear burning on the onset of the neutrino-driven explosions of core-collapse supernovae. By changing the neutrino luminosity and its decay time to obtain parametric explosions in one-(1D) and two-dimensional (2D) models with or without a 13-isotope alpha network, we study how the inclusion of nuclear burning could affect the postbounce dynamics for four progenitor models; three for 15.0 Msun stars, one for an 11.2 Msun star. We find that the energy supply due to nuclear burning of infalling material behind the shock can energize the shock expansion especially for models that produce only marginal explosions in the absence of nuclear burning. These models are energized by nuclear energy deposition when the shock front passes through the silicon-rich layer and/or later it touches the oxygen-rich layer. Depending on the neutrino luminosity and its decay time, a diagnostic energy of explosion increases up to a few times 10^50 erg for models with nuclear burning compared to the corresponding models without. We point out that these features are most remarkable for the Limongi-Chieffi progenitor in both 1D and 2D, because the progenitor model possesses a massive oxygen layer with its inner-edge radius being smallest among the employed progenitors, so that the shock can touch the rich fuel on a shorter timescale after bounce. The energy difference is generally smaller (~0.1-0.2 times 10^51 erg) in 2D than in 1D (at most ~0.6 times 10^51 erg). This is because neutrino-driven convection and the shock instability in 2D models enhance the neutrino heating efficiency, which makes the contribution of nuclear burning relatively smaller compared to 1D models. Considering uncertainties in progenitor models, our results indicate that nuclear burning should remain as one of the important ingredients to foster the onset of neutrino-driven explosions. 
Ko Nakamura, Tomoya Takiwaki, Kei Kotake, and Nobuya Nishimura
astro-ph.HE