Seeding the second star: Enrichment from population III, dust evolution, and cloud collapse

Gen Chiaki, John H. Wise

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)

Abstract

We investigate the formation of extremely metal-poor (EMP) stars that are observed in the Galactic halo and neighbouring ultra-faint dwarf galaxies. Their low metal abundances ([Fe/H] < -3) indicate that their parent clouds were enriched by a single or several supernovae (SNe) from the first (Pop III) stars. In this study, we perform numerical simulations of the entire formation sequence of an EMP star through the feedback effects of photoionization and metalenrichment by a Pop III SN. We for the first time employ a metal/dust properties calculated consistently with the progenitor model, and solve all relevant radiative cooling processes and chemical reactions including metal molecular formation and grain growth until the protostar formation. In a minihalo (MH) with mass 1.77 × 106M, a Pop III star with mass 13M forms at redshift z = 12.1. After its SN explosion, the shocked gas falls back into the central MH internally enriching itself. The metallicity in the recollapsing region is 2.6 × 10-4 Z ([Fe/H]=-3.42). The recollapsing cloud undergoes cooling by HD, CO, and OH molecules and heating along with H2 formation. Eventually by grain growth and dust cooling, knotty filaments appear in the central 100 au region with the help of turbulence driven by the SN, leading to the formation of low-mass EMP stars surviving until the present day. 2018 The Author(s).

Original languageEnglish
Pages (from-to)3933-3949
Number of pages17
JournalMonthly Notices of the Royal Astronomical Society
Volume482
Issue number3
DOIs
Publication statusPublished - 2019 Jan 21
Externally publishedYes

Keywords

  • Abundances-galaxies
  • Evolution
  • Formation-stars
  • Low-mass-stars
  • Population II-stars
  • Population III-ism
  • Stars

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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