Formation of Population III Stars in a flat FLRW Universe

Abstract

Contrarily to general believe, a first-order cosmological perturbation theory based on Einstein's General Theory of Relativity explains the formation of massive primeval stars in a flat Friedmann-Lemaitre-Robertson-Walker universe after decoupling of matter and radiation, whether or not Cold Dark Matter is present. The growth rate of a density perturbation depends on the heat loss of a perturbation during the contraction, but is independent of the particle mass. The relativistic Jeans mass does depend on the particle mass. If the Cold Dark Matter particle mass is equal to the proton mass, then the relativistic Jeans mass is equal to 3500 solar masses, whereas the classical Jeans mass is a factor 145 larger.