The Formation of Population III Binaries from Cosmological Initial
  Conditions
  Previous high resolution cosmological simulations predict the first stars to
appear in the early universe to be very massive and to form in isolation. Here
we discuss a cosmological simulation in which the central 50 solar mass clump
breaks up into two cores, having a mass ratio of two to one, with one fragment
collapsing to densities of 10^{-8} g/cc. The second fragment, at a distance of
800 astronomical units, is also optically thick to its own cooling radiation
from molecular hydrogen lines, but is still able to cool via collision-induced
emission. The two dense peaks will continue to accrete from the surrounding
cold gas reservoir over a period of 10^5 years and will likely form a binary
star system.
