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

Jan 30, 2019
33 pages
Published in:
  • Astrophys.J. 887 (2019) 72
e-Print:
DOI:

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Abstract: (arXiv)
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 the initial masses of 8014080 - 140 MM_{\odot} and metallicities of Z=1031.0Z = 10^{-3} - 1.0 ZZ_\odot. Because of mass loss, Z0.5Z \leq 0.5 ZZ_\odot is necessary for stars to form He cores massive enough (i.e., mass >40 M>40 ~M_\odot) to undergo PPI. The hydrodynamical phase of evolution from PPI through the beginning of Fe core collapse is calculated for the He cores with masses of 4062 M40 - 62 ~M_\odot and Z=0Z = 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 such a large amount of mass ejection such as 3133 - 13 MM_\odot for 4062 M40 - 62 ~M_\odot He cores. These He cores eventually undergo Fe-core collapse. The 64 M64 ~M_\odot He core undergoes complete disruption and becomes a pair-instability supernova. The H-free circumstellar matter ejected around these He cores is massive enough for 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\sim 50 MM_{\odot}, which is consistent with the masses of BHs recently detected by VIRGO and aLIGO.
Note:
  • 33 pages, 57 figures, submitted at 29 January 2019, revised at 16 October 2019, accepted at 20 October 2019; published 11 December 2019. References and metadata updated
  • electron: pair production
  • mass: ejection
  • black hole: mass
  • star: massive
  • supernova
  • mass dependence
  • thermodynamics
  • hydrodynamics
  • collapse