On the Core-Collapse Supernova Explanation for LAMOST J1010+2358

TL;DR

This study compares nucleosynthesis models of core-collapse supernovae and pair-instability supernovae to explain the peculiar abundance pattern of the very metal-poor star LAMOST J1010+2358, finding CCSN models fit equally well or better.

Contribution

It demonstrates that the abundance pattern of LAMOST J1010+2358 can be explained by core-collapse supernova models, challenging the initial PISN interpretation and identifying key future measurements.

Findings

CCSN models of 12-14 M_ can fit the star's abundance pattern.

Best-fit CCSN models outperform PISN models in fitting the data.

Unambiguous identification of PISN origin requires measuring additional elemental abundances.

Abstract

Low-metallicity very massive stars with an initial mass of $\sim 140$--$260\, {\rm M_\odot}$ are expected to end their lives as pair-instability supernovae (PISNe). The abundance pattern resulting from a PISN differs drastically from regular core-collapse supernova (CCSN) models and is expected to be seen in very metal-poor (VMP) stars of ${\rm[Fe/H]}\lesssim -2$. Despite the routine discovery of many VMP stars, the unique abundance pattern expected from PISNe has not been unambiguously detected. The recently discovered VMP star LAMOST J1010+2358, however, shows a peculiar abundance pattern that is remarkably well fit by a PISN, indicating the potential first discovery of a bonafide star born from gas polluted by a PISN. In this paper, we study the detailed nucleosynthesis in a large set of models of CCSN of Pop III and Pop II star of metallicity ${\rm[Fe/H]}=-3$ with masses ranging from $12$--$30\,{\rm M_\odot}$. We find that the observed abundance pattern in LAMOST J1010+2358 can be fit at least equally well by CCSN models of $\sim 12$--$14\,{\rm M_\odot}$ that undergo negligible fallback following the explosion. The best-fit CCSN models provide a fit that is even marginally better than the best-fit PISN model. We conclude the measured abundance pattern in LAMOST J1010+2358 could have originated from a CCSN and therefore cannot be unambiguously identified with a PISN given the set of elements measured in it to date. We identify key elements that need to be measured in future detections in stars like LAMOST J1010+2358 that can differentiate between CCSN and PISN origin.