Metal-enriched Pair-instability Supernovae: Effects of Rotation

Abstract

In this paper, we revisit metal-enriched rotating pair-instability supernovae (PISNe) models for metallicities consistent with the Small Magellanic Cloud, the Large Magellanic Cloud (LMC), and 0.1Z ⊙. By calculating multiple models, we intend to clarify mass ranges and the ejected 56Ni masses from the PISNe, and mass-loss histories for progenitors. We find that the choice of the Wolf–Rayet (WR) mass-loss rates is important, and we adopt the recently proposed rate of Sander & Vink, which covers the mass ranges for PISNe progenitors. We show that slow rotation lowers the PISN range because the core mass increases by rotational mixing. On the other hand, when we assume a typical rotation speed for observed OB stars, the mass-loss increase becomes more significant, and the final stellar masses are lower than in nonrotating models. As a result, the typical mass range for bright supernovae (SNe), with a 56Ni mass higher than 10M ⊙ for these fast-rotating models is more than 400 and 350M ⊙ for LMC and 0.1Z ⊙ metallicities, respectively. It is interesting that unlike in previous works, we find oxygen-rich progenitors for most cases. This O-rich progenitor may be consistent with the recently identified PISN candidate SN2018ibb. He-rich progenitors are seen only for relatively dim and metal-poor (Z ≲ 0.1Z ⊙) PISNe. We also discuss the black hole mass gap for metal-enriched PISNe, and we show that the upper bound for the gap is lower than in the Population III case.