Formation environment of Pop II stars affected by the feedbacks from Pop III stars

Stars with metallicities [Fe/H] <-3 are called extremely metal-poor (EMP) stars, and considered to be formed in clouds enriched with metal from a single or several supernovae (SNe) of the first-generation (Pop III) stars. To confirm this, we numerically follow the enrichment process of minihalos (MHs) which have hosted Pop III stars. During their main-sequence (MS), the ionizing photons can not or partly break the gas around the Pop III stars because the halo binding energy is marginally larger than the radiation energy. After SN explosions, the gas continues to accrete along filaments of the large-scale structures, and the gas collapses again in the MHs within ∼ 10 Myr for low-mass MHs (3 × 10⁵ M^⊙) while ∼ 1 Myr for massive MHs (3 × 10⁶ M^⊙). The metallicity in the recollapsing regions is 10^-4-10^-2 Z^⊙ and 10^-6-10^-5 Z^⊙, respectively. This indicates that EMP stars are formed in the clouds enriched by a single SN in low-mass MHs.