Three-dimensional hydrodynamical simulations unravel the evolution of SN 1987A from the explosion to the supernova remnant

Dr. Masaomi Ono

RIKEN

Abstract: Supernova 1987A (SN 1987A) provides a unique opportunity to unravel the  evolution of core-collapse supernovae (CCSNe) from the explosions to  their supernova remnants (SNRs) thanks to its proximity and youth. Early  observation of iron lines has indicated matter mixing during the  explosion to convey innermost 56Ni to outer layers. Since the density  structure of the progenitor star affects the matter mixing, it provides  a hint on the properties of the progenitor star. In the meanwhile,  continuous observations in X-ray bands have provided clues to understand the evolution at early SNR phases.

We perform three-dimensional (3D) hydrodynamical/magnetohydrodynamical simulations of aspherical CCSNe from the onset of the explosion to an early SNR phase. The impacts of the progenitor models and parameterized aspherical explosions are investigated. The progenitor models include ones based on both the single star and binary merger scenarios. Among the models, a model with an asymmetric jetlike explosion of a binary merger progenitor, which has an advantage in explaining the features of the progenitor star and the triple-ring nebula around SN 1987A, best reproduces the observations of SN 1987A (iron lines and X-ray light curves). From the best model, the directions of the strongest explosion and the neutron star (NS) kick velocity are predicted.

Recent observations of SN 1987A by ALMA have shown 3D spatial distributions of two diatomic molecules, CO and SiO, in the ejecta for the first time. Subsequent ALMA observations have also revealed a hotspot in dust emission from the ejecta, which has been interpreted as an evidence of the (undetected) NS. Our attempts to unveil the chemical evolution of the ejecta with molecule formation calculations and the properties of the NS with X-ray analyses are also presented briefly.