The First Population II Stars Formed in Externally Enriched Mini-halos

Understand

We present a simulation of the formation of the earliest Population II stars, starting from cosmological initial conditions and ending when metals created in the first supernovae are incorporated into a collapsing gas-cloud.

• This occurs after a supernova blast-wave collides with a nearby mini-halo, inducing further turbulence that efficiently mixes metals into the dense gas in the center of the halo.
• The gas that first collapses has been enriched to a metallicity of Z ~ 2e-5 Zsun.
• Due to the extremely low metallicity, collapse proceeds similarly to metal-free gas until dust cooling becomes efficient at high densities, causing the cloud to fragment into a large number of low mass objects.