ABSTRACT

We present the results from an ultra-high resolution cosmological simulation of the formation of primordial stars. Our approach include all the relevant atomic and molecular processes to follow the thermal and chemical evolution of a primordial gas cloud to densities ~10^{21} per cc, without assuming any a priri equation of state. We, for the first time, reveal the entire formation process of an astronomical object - a tiny protostar - from density fluctuations leftover from the Big Bang. The first star-forming gas cloud is in place in a cosmological mini dark halo with a mass of a million solarmasses, when the age of the universe if 300 million years old. The cloud has a baryonic mass of a few hundred solarmasses. The very central part continues collapsing until a small hydrostatic core with temperature ~10000K is formed. The core (protostar) has a mass of 0.01 Msun and a radius of 5x10^{11} cm. At the final output time, we see a complex internal structure within a core induced by accretion shocks. We show various gas quantities around the protostar. The protostar is surrounded with a large amount of high-temperature gas, and it is expected to grow quickly to be as massive as 100 solarmasses. We discuss the implications of our result for elemental abundance patterns in Galactic metal-poor halo stars.