Metal-poor star formation triggered by the feedback effects from Pop III stars

Gen Chiaki, Hajime Susa, Shingo Hirano

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)

Abstract

Metal enrichment by first-generation (Pop III) stars is the very first step of the matter cycle in structure formation and it is followed by the formation of extremely metal-poor (EMP) stars. To investigate the enrichment process by Pop III stars, we carry out a series of numerical simulations including the feedback effects of photoionization and supernovae (SNe) of Pop III stars with a range of masses of minihaloes (MHs), Mhalo, and Pop III stars, MPopIII. We find that the metal-rich ejecta reach neighbouring haloes and external enrichment (EE) occurs when the HII region expands before the SN explosion. The neighbouring haloes are only superficially enriched, and the metallicity of the clouds is [Fe/H] < -5. Otherwise, the SN ejecta fall back and recollapse to form an enriched cloud, i.e. an internal-enrichment (IE) process takes place. In the case where a Pop III star explodes as a core-collapse SN (CCSN), the MH undergoes IE, and the metallicity in the recollapsing region is -5 ≲ [Fe/H] ≲ -3 in most cases. We conclude that IE from a single CCSN can explain the formation of EMP stars. For pair-instability SNe (PISNe), EE takes place for all relevant mass ranges of MHs, consistent with the lack of observational signs of PISNe among EMP stars.

Original languageEnglish
Pages (from-to)4378-4395
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume475
Issue number4
DOIs
Publication statusPublished - 2018 Apr 21
Externally publishedYes

Keywords

  • Galaxies: evolution
  • ISM: abundances
  • Stars: Population II
  • Stars: Population III
  • Stars: formation
  • Stars: low-mass

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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