Stellar Yields of Rotating First Stars. I. Yields of Weak Supernovae and Abundances of Carbon-enhanced Hyper Metal Poor Stars

TL;DR

This study models the evolution and yields of the first stars, considering rotation and weak supernova explosions, to explain the observed abundances in hyper metal-poor stars and constrain progenitor properties.

Contribution

It introduces stellar evolution simulations with rotation and weak explosions to connect first star properties with observed metal-poor star abundances.

Findings

All weak explosion models have [C/O] > 1.

Massive progenitors > 40-60 Msun show Mg and Si enhancement.

Rotating models produce abundant Na and Al.

Abstract

We perform stellar evolution simulation of first stars and calculate stellar yields from the first supernovae. The initial masses are taken from 12 to 140 Msun to cover the whole range of core-collapse supernova progenitors, and stellar rotation is included, which results in efficient internal mixing. A weak explosion is assumed in supernova yield calculations, thus only outer distributed matter, which is not affected by the explosive nucleosynthesis, is ejected in the models. We show that the initial mass and the rotation affect the explosion yield. All the weak explosion models have abundances of [C/O] larger than unity. Stellar yields from massive progenitors of > 40-60 Msun show enhancement of Mg and Si. Rotating models yield abundant Na and Al. And Ca is synthesized in non-rotating heavy massive models of > 80 Msun. We fit the stellar yields to the three most iron-deficient stars, and constrain the initial parameters of the mother progenitor stars. The abundance pattern in SMSS 0313-6708 is well explained by 50-80 Msun non-rotating models, rotating 30-40 Msun models well fit the abundance of HE 0107-5240, and both non-rotating and rotating 15-40 Msun models explain HE 1327-2326. The presented analysis will be applicable to other carbon-enhanced hyper metal poor stars observed in the future. The abundance analyses will give valuable information about the characteristics about the first stars.