2012/11/30 by Athena Stacy, Volker Bromm · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stt789
16 pages, 14 figures, to appear in MNRAS
arxiv created 2013/05/18 · arxiv updated 2015/06/12
We perform a cosmological simulation in order to model the growth and evolution of Population III (Pop III) stellar systems in a range of host minihalo environments. A Pop III multiple system forms in each of the ten minihaloes, and the overall mass function is top-heavy compared to the currently observed initial mass function in the Milky Way. Using a sink particle to represent each growing protostar, we examine the binary characteristics of the multiple systems, resolving orbits on scales as small as 20 AU. We find a binary fraction of ~36%, with semi-major axes as large as 3000 AU. The distribution of orbital periods is slightly peaked at < 900 yr, while the distribution of mass ratios is relatively flat. Of all sink particles formed within the ten minihaloes, ~50% are lost to mergers with larger sinks, and ~50% of the remaining sinks are ejected from their star-forming disks. The large binary fraction may have important implications for Pop III evolution and nucleosynthesis, as well as the final fate of the first stars.