Seeding the second star: enrichment from population III, dust evolution, and cloud collapse. Issue 3 (3rd November 2018)

• Record Type: Journal Article
• Authors: Chiaki, Gen; Wise, John H
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 482:Issue 3(2019)
• Page Start: 3933
• Page End: 3949
• Publication Date: 2018-11-03
• Subjects: stars: formation -- stars: low-mass -- stars: Population II -- stars: Population III -- ISM: abundances -- galaxies: evolution; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/sty2984
• Languages: English
• ISSNs: 0035-8711

Abstract

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 metal-enrichment 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 $1.77\times 10^{6}\, {\rm M_{\bigodot }}$, a Pop III star with mass $13\, {\rm M_{\bigodot }}$ 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 $2.6\times 10^{-4}\, {\rm Z_{\bigodot }}$ ([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.