An unexplored enrichment stochasticity and its implications for stellar abundance patterns

Abstract

Extremely low metallicity stars are intensely studied as they take observations the closest to the very first generations of stars in the universe. Widely assumed to be enriched by just one dying massive star, some of these very metal poor stars have abnormal chemical abundance ratios and have been taken to reflect a rare hypernova (with high explosion energy $\gtrsim 10^{52}$ erg.). Here we remodel the enrichment of three such stars and show that their abundances are better explained by enrichment from a normal (less energetic) supernova accounting for inhomogeneous distribution of the ejecta. This work establishes the importance of the inhomogeneity of supernovae, serves as a template for a required reassessment of all metal-poor/peculiar stars, and raises the need to quantify this inhomogeneity both in theory and in observations.

12 pages, 13 Figures, 6 Tables, accepted for publication in MNRAS