TY - JOUR
T1 - The birth mass function of Pop III stars
AU - Latif, Muhammad A.
AU - Whalen, Daniel
AU - Khochfar, Sadegh
N1 - Rights statement: 'This Accepted Manuscript is available for reuse under a CC BY-NC-ND licence after the 12 month embargo period provided that all the terms of the licence are adhered to.'
PY - 2021/11/10
Y1 - 2021/11/10
N2 - Population III (Pop III) stars ended the cosmic Dark Ages and began early cosmological reionization and chemical enrichment. However, in spite of their importance to the evolution of the early Universe, their properties remain uncertain because of limitations to previous numerical simulations and the lack of any observational constraints. Here we investigate Pop III star formation in five primordial halos with 3D radiation-hydrodynamical cosmological simulations. We find that multiple stars form in each minihalo and that their numbers increase over time, with up to 23 stars forming in one of the halos. Radiative feedback from the stars generates strong outflows, deforms the surrounding protostellar disk, and delays star formation for a few thousand years. Star formation rates vary with halo and depend on mass accretion onto the disk, halo spin number, and the fraction of massive stars in the halo. Stellar masses in our models range from 0.1-37 M⊙ , and of the 55 stars that form in our models twelve are >10 M⊙ and most of the others are 1-10 M⊙ . Our simulations thus suggest that Pop III stars have characteristic masses of 1-10 M⊙ and a top-heavy IMF with dN/dM ∝ M*−1.18. Up to 70% of the stars are ejected from their disks by three-body interactions which, along with ionizing UV feedback, limits their final masses.
AB - Population III (Pop III) stars ended the cosmic Dark Ages and began early cosmological reionization and chemical enrichment. However, in spite of their importance to the evolution of the early Universe, their properties remain uncertain because of limitations to previous numerical simulations and the lack of any observational constraints. Here we investigate Pop III star formation in five primordial halos with 3D radiation-hydrodynamical cosmological simulations. We find that multiple stars form in each minihalo and that their numbers increase over time, with up to 23 stars forming in one of the halos. Radiative feedback from the stars generates strong outflows, deforms the surrounding protostellar disk, and delays star formation for a few thousand years. Star formation rates vary with halo and depend on mass accretion onto the disk, halo spin number, and the fraction of massive stars in the halo. Stellar masses in our models range from 0.1-37 M⊙ , and of the 55 stars that form in our models twelve are >10 M⊙ and most of the others are 1-10 M⊙ . Our simulations thus suggest that Pop III stars have characteristic masses of 1-10 M⊙ and a top-heavy IMF with dN/dM ∝ M*−1.18. Up to 70% of the stars are ejected from their disks by three-body interactions which, along with ionizing UV feedback, limits their final masses.
KW - method: numerical
KW - early universe
KW - galaxies: high-redshift
KW - dark ages, reionization, first stars
UR - https://arxiv.org/abs/2109.10655
M3 - Article
SN - 0004-637X
JO - The Astrophysical Journal
JF - The Astrophysical Journal
ER -