Primordial star formation: relative impact of H

Context. Population III stars are the first stars in the Universe to form at z = 20–30 out of a pure hydrogen and helium gas in minihalos of 105−106M⊙. Cooling and fragmentation is thus regulated via molecular hydrogen. At densities above 108 cm-3, the three-body H2 formation rates are particularly important for making the gas fully molecular. These rates were considered to be uncertain by at least a few orders of magnitude. Aims. We explore the impact of recently derived accurate three-body H2 formation for three different minihalos, and compare them with the results obtained with three-body rates employed in previous other studies. Methods. The calculations were performed with the cosmological hydrodynamics code enz