Effects of Rotation on 3D Core-Collapse Supernova Models for Low-Mass Progenitors

Abstract

We explore the dependence upon rotation rate alone of various supernova observables simulated to their saturation for the explosion of a 9-$M_{\odot}$ progenitor. We find that the explosion energy is non-monotonic with, and weakly dependent upon, spin across a broad range of initial spins. The asymmetries of the blast depend weakly on spin, with faster spins leading to only slightly greater asymmetries. There is little significant pole-equator neutrino heating asymmetry during explosion, even for rapid rotation, and only for the fastest rotator does the neutrino heating rate diminish noticeably. Hence, the effects of rotation alone on all salient aspects of supernova dynamics are not large. We find that the recoil kick and spin are clearly aligned only for the most rapidly rotating model. Interestingly, for the fastest rotator, we witness a $T/|W|$ corotation instabilities near a value of 0.05 and spiral arm modes emerge. We find that the nucleosynthetic yields depend little upon the rotation rate and determine that the ratio of initial to final core spin period is near $\sim$4000, implying, given the modest inferred radio pulsar periods at birth, that the initial spin periods of most supernova cores are likely quite long. However, we focus on only one progenitor and do not include magnetic fields. Nevertheless, at least for low-mass progenitors which explode early, we find muted consequences of rotation in most major particulars across a wide range of initial spins.