Stochastic mixing of core-collapse supernova and neutron star merger yields fits halo star abundances better than single magnetorotational hypernova

The arXiv preprint demonstrates that previously claimed evidence for a magnetorotational hypernova origin rested on assuming a single-event yield without accounting for inhomogeneous mixing in the birth cloud. When stochastic mixing between a standard 10^51 erg core-collapse supernova and a neutron star merger is allowed, the observed pattern of light and heavy elements matches more closely. This reframes the star as the product of two common enrichment events rather than one rare hypernova.

Context from galactic chemical evolution models indicates that early halo stars frequently sample mixed ejecta from multiple sources separated by tens of parsecs and Myr timescales. The superior rms fit undermines the necessity of invoking magnetorotational hypernovae to explain r-process enhanced stars with otherwise ordinary iron-peak ratios. High-resolution spectra of additional metal-poor stars will be required to test whether this pattern is common or exceptional.

Future observations with ELT and JWST will measure isotopic ratios and neutron-capture elements at higher precision, providing a direct test of whether stochastic mixing or single exotic events dominate the abundance scatter at [Fe/H] < -2. If the stochastic model holds, current yields libraries for hypernovae will need recalibration against multi-event enrichment scenarios.