Metal-enriched Pair-instability supernovae: Effects of rotation

TL;DR

This study models metal-enriched rotating pair-instability supernovae at various metallicities, revealing how rotation and mass loss influence progenitor characteristics, supernova brightness, and black hole mass gaps, with implications for observed supernovae like SN2018ibb.

Contribution

It provides new insights into the effects of rotation and updated mass-loss rates on PISN progenitors at different metallicities, expanding understanding of supernova outcomes and black hole formation.

Findings

Rotation affects the PISN mass range and core mass.

Fast rotation leads to more massive, oxygen-rich progenitors.

The black hole mass gap is lower than in Population III stars.

Abstract

In this paper we revisit metal-enriched rotating pair instability supernovae (PISNe) models for metallicities consistent with the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC) and 0.1$Z_\odot$. By calculating multiple models, we intend to clarify mass ranges and the ejected $^{56}$Ni masses from the PISNe, and mass loss histories for progenitors. We find the choice of the Wolf-Rayet (WR) mass-loss rates are important and we adopt the recently proposed rate of Sander & Vink (2020), which covers the mass ranges for PISNe progenitors. We show that slow rotation lowers the PISN range due to the increase in core mass by rotational mixing. On the other hand, if we assume typical rotation speed for observed OB stars, the mass loss increase becomes more significant and the final stellar masses are smaller than non-rotating models. As a result, typical mass range for bright SNe, with $^{56}$Ni mass more than 10${ M}_\odot$ for such fast rotating models are more than 400, 350 ${ M}_\odot$, for LMC and 0.1$Z_\odot$ metallicities, respectively. It is interesting that, unlike 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 ($Z \lesssim 0.1 Z_\odot$) PISNe. We also discuss the black hole mass gap for metal-enriched PISNe, and show that the upperbound for the gap is lower than in the Pop III case.