Primordial star formation: relative impact of H2three-body rates and initial conditions

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.