Pulsational Pair-instability Supernovae: Gravitational Collapse, Black-hole Formation, and BeyondONLINE ONLY

A very massive star with a mass of around 100 M⊙ can experience pulsational pair-instability in the post-carbon burning phase. We study the gravitational collapse of two rotating very massive star progenitors with zero-age-main-sequence masses of 60 M⊙ and 80 M⊙ and of a non-rotating 115 M⊙ very massive star progenitor. We also investigate these ZAMS 60 M⊙ and 80 M⊙ progenitors neglecting their rotation during the CCSN simulations. In our simulations, we observe shock revival by the neutrino heating, aided by hydrodynamical instabilities, in all cases except for the rapidly rotating 60 M⊙ model. Due to the ongoing accretion onto the proto-neutron star, eventually, black holes are formed in all our models. In the non-rotating 60 M⊙ model, the revived shock reaches the stellar surface even after the black hole formation and unbounds around 0.04 M⊙ of stellar material. In all other models with shock revival, the shocks are dissolved, however, the hydrodynamical discontinuities of dying shocks are replaced by sonic pulses which propagate radially outwards and transport energy. When the sonic pulse reaches a mass shell near the surface of the star whose absolute value of total energy is smaller than the energy carried by pulse, then that mass shell becomes gravitationally unbound and the star losses mass. Here, we present a crude estimate for the upper limit of mass losses due to sonic pulse. The upper limits of the baryonic mass loss are about 2.11 M⊙, 2.65 M⊙ for the non-rotating 80 M⊙ model and its rotating counterpart, respectively. In the non-rotating 115 M⊙ model, the baryonic mass loss is around 0.1 M⊙.