Triggering jet-driven explosions of core-collapse supernovae by accretion from convective regions

We find that convective regions of collapsing massive stellar cores possess sufficient stochastic angular momentum to form intermittent accretion discs around the newly born neutron star (NS) or black hole (BH), as required by the jittering-jets model for core-collapse supernova explosions. To reach this conclusion, we derive an approximate expression for stochastic specific angular momentum in convection layers of stars, and using the mixing-length theory apply it to four stellar models at core-collapse epoch. In all models, evolved using the stellar evolution code MESA, the convective helium layer has sufficient angular momentum to form an accretion disc. The mass available for disc formation around the NS or BH is 0.1-1.2M_⊙stochastic accretion of thismass can form intermittent accretion discs that launch jets, powerful enough to explode the star according to the jittering-jets model. Our results imply that even if no explosion occurs after accretion of the inner ̃2-5M_⊙ of the core on to the NS or BH (the mass depends on the stellar model), accretion of outer layers of the core will eventually lead to an energetic supernova explosion.