Pair-Instability Supernovae of Fast Rotating Stars

TL;DR

This study uses 2D simulations to explore how rapid rotation affects pair-instability supernovae in massive, fast-rotating Pop III stars, revealing aspherical explosions and reduced nickel production.

Contribution

It introduces the first 2D models of rotating pair-instability supernovae, highlighting the impact of rotation on explosion asymmetry and nucleosynthesis.

Findings

Rotation causes aspherical explosions due to anisotropic collapse.

High rotation rates significantly reduce nickel production.

Fluid instabilities like Richtmyer-Meshkov are triggered by non-synchronized ignitions.

Abstract

We present 2D simulations of pair-instability supernovae considering rapid rotation during their explosion phases. Recent studies of the Pop III star formation suggested that these stars could be born with a mass scale about 100 Msun and with a strong rotation. Based on stellar evolution models, these massive Pop III stars might have died as highly energetic pair-instability supernovae. We perform 2D calculations to investigate the impact of rotation on pair-instability supernovae. Our results suggest that rotation leads to an aspherical explosion due to an anisotropic collapse. If the first stars have a 50% of keplerian rotational rate of the oxygen core before their pair-instability explosions, the overall Ni production can be significantly reduced by about two orders of magnitude. An extreme case of 100% keplerian rotational rate shows an interesting feature of fluid instabilities along the equatorial plane caused by non-synchronized and non-isotropic ignitions of explosions, so that the shocks run into the in-falling gas and generate the Richtmyer--Meshkov instability.