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Formation channel of PPISN progenitors at moderate metallicity

Ascertain whether pulsational pair-instability supernova progenitors at metallicities around 0.4 Z⊙ can be formed in situ through single-star evolution or whether they must instead be produced via close binary mergers, in order to explain the progenitor of SN2020acct.

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Background

The local environment of SN2020acct has a metallicity of approximately 0.4 Z⊙, higher than the ∼0.1 Z⊙ typically assumed for single-star models that reach the pulsational pair-instability regime. The authors discuss that late binary mergers could produce sufficiently massive helium cores at higher metallicity, or that a low-metallicity pocket might exist locally.

Population-synthesis considerations and rate estimates are consistent with rarity, but do not resolve which channel applies in this case. High-resolution environmental studies are suggested to discriminate between these possibilities.

References

It is unclear whether such PPI progenitors may be formed in situ at higher metallicity, or must be produced via close binaries mergers (e.g. Vigna-G´omez et al. 2019), with further detailed studies of the local environment required to settle the discrepancy.

— Double "acct": a distinct double-peaked supernova matching pulsational pair-instability models (2409.02174 - Angus et al., 3 Sep 2024) in Section 6 (Conclusions)