Pulsational Pair-instability Supernovae. I. Pre-collapse Evolution and Pulsational Mass Ejection

Abstract

We calculate the evolution of massive stars, which undergo pulsational pair-instability (PPI) when the O-rich core is formed. The evolution from the main sequence through the onset of PPI is calculated for stars with initial masses of 80-140 M e and metallicities of Z=10 −3 −1.0 Z e. Because of mass loss, Z0.5 Z e is necessary for stars to form He cores massive enough (i.e., mass >40 M e) to undergo PPI. The hydrodynamical phase of evolution from PPI through the beginning of Fe-core collapse is calculated for He cores with masses of 40−62 M e and Z=0. During PPI, electron-positron pair production causes a rapid contraction of the O-rich core, which triggers explosive O-burning and a pulsation of the core. We study the mass dependence of the pulsation dynamics, thermodynamics, and nucleosynthesis. The pulsations are stronger for more massive He cores and result in a large amount of mass ejection such as 3-13 M e for 40−62 M e He cores. These He cores eventually undergo Fe-core collapse. The 64 M e He core undergoes complete disruption and becomes a pair-instability supernova. The H-free circumstellar matter ejected around these He cores is massive enough to explain the observed light curve of Type I (H-free) superluminous supernovae with circumstellar interaction. We also note that the mass ejection sets the maximum mass of black holes (BHs) to be ∼50 M e , which is consistent with the masses of BHs recently detected by VIRGO and aLIGO.

Constraints from Gravitational-wave Detections of Binary Black Hole Mergers on the 12C(α, γ)16O Rate

“…Further work is needed to understand the collapse mechanism of these massive cores, and whether we can extrapolate from models of stars that collapse with cores of M 5 10 - to those with cores of » M 50  . Previous studies of PPISN and PISN progenitors have found the location of the PISN mass gap consistent with ours, M 50 53 - (Yoshida et al 2016), » M 48  (Woosley 2017), » M 50  (Leung et al 2019). The small variations in the location of the gap can be attributed to differences in chosen metallicity, mass loss rates, and source of the a g C , O…”

Standing on the Shoulders of Giants: New Mass and Distance Estimates for Betelgeuse through Combined Evolutionary, Asteroseismic, and Hydrodynamic Simulations with MESA

“…This includes = = = = = = These settings have been used in our previous work modeling the dynamical pulsation in pulsation pair-instability supernovae. See Leung et al (2019Leung et al ( , 2020 for the application of these setting to the more massive star counterpart. Furthermore, to ensure the code captures the early oscillation when the simulation has begun, we impose a maximum evolutionary timestep of 10 5 s: = _ max timestep 100000…”

Beyond the Standard Model Explanations of GW190521

“…Using an old version of the numerical code MESA and the assumption that the entire He+C+O stellar core after pulsations becomes a black hole -in reality, only bound material contributes -Ref. [12] reports a black hole mass slightly in excess of the value found in Ref. [4].…”