Ching-Yao Tang(NTU); Ke-Jung Chen(ASIAA)
The first stars (Pop III stars) play a paramount role in the early universe. Therefore, understanding the physical processes of their formation is essential to studying the early universe’s evolution. Previous cosmological simulations have suggested that the typical mass scale of the Pop III stars are around 100 - 1000 solar masses. However, this result is inconsistent with the recent observations of the extremely metal-poor stars (EMP stars) which infer they should be around 20 - 60 solar masses. This mass deviations can be due to the lack of the subtle hydrodynamic structures of the driven turbulence during the Pop III star formation. To validate the effect of turbulence, we employ the adaptive mesh refinement (AMR) code Enzo and the stochastic forcing model to simulate the accretion of the primordial gas in a mini-halo, which is full of the turbulent gas. Then the inhomogeneous gas density driven by turbulence evolves to form stars. Our simulations have included all the relevant physics of Pop III star formation, such as primordial gas cooling, star formation with sink particles, and feedback from stellar radiation. Finally, we investigate the strength of turbulence on the Pop III star formation and compare our results with the observation of EMP stars.