Copyright by Athena Ranice Stacy 2011 - The University of Texas at ...

Chapter 7
Outlook
Our understanding of the early universe and the first stars has grown
rapidly over just the last several years. The picture of lone, highly massive
Pop III stars has now expanded to include disk formation with possible co-
formation of low-mass companion Pop III stars. A build-up of a cosmic ray
background may also lead to population of relatively small primordial stars.
Though results of various simulations still point to a top-heavy IMF, the range
of possible Pop III masses is probably much larger than initially thought. Over-
all, as computational power and numerical simulations continue to improve,
we are finding that the physical processes necessary to describe Pop III star
formation are becoming increasingly similar those describing star formation in
our own Milky Way. Disk formation, fragmentation, and stellar rotation are
important to consider when studying star formation not only at z = 0, but at
all redshifts.
In Chapter 2, we investigated the formation of metal-free, Pop III,
stars within a minihalo at z 20 with a numerical simulation starting from
cosmological initial conditions. Beginning from z = 100, we followed the
collapsing gas in the center of the minihalo up to number densities of 10 12 cm −3 .
This allowed us to study the accretion onto the initial protostellar hydrostatic
core, which we represent as a growing sink particle, in improved physical detail.
A disk-like configuration assembles around the first protostar, and eventually a
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