Nucleosynthesis in Primordial Hypernovae

Abstract

We investigate the relationship between explosion energy and nucleosynthesis in Population III supernovae and provide nucleosynthetic results for the explosions of stars with progenitor masses of $15{\mathrm{M}}_{\odot }$, $20{\mathrm{M}}_{\odot }$, $30{\mathrm{M}}_{\odot }$, $40{\mathrm{M}}_{\odot }$, $60{\mathrm{M}}_{\odot }$, and $80{\mathrm{M}}_{\odot }$, and explosion energies between approximately $10^{50}$ erg and $10^{53}$ erg. We find that the typical abundance pattern observed in metal-poor stars are best matched by supernovae with progenitor mass in the range $15{\mathrm{M}}_{\odot }$ - $30{\mathrm{M}}_{\odot }$, and explosion energy of $\sim$ ($5$ - $10$) $\times$ $10^{51}$ erg. In these models, a reverse shock caused by jumps in density between shells of different composition serves to decrease synthesis of chromium and manganese, which is favourable to matching the observed abundances in metal-poor stars. Spherically symmetric explosions of our models with progenitor mass $\ge$ $40{\mathrm{M}}_{\odot }$ do not provide yields that are compatible with the iron-peak abundances that are typically observed in metal-poor stars, however, by approximating the yields that we might expect from these models in highly aspherical explosions, we find indications that explosions of stars $40{\mathrm{M}}_{\odot }$ - $80{\mathrm{M}}_{\odot }$ with bipolar jets may be good candidates for the enrichment sources of metal-poor stars with enhanced carbon abundances.