Matthew R. Bate
The Astrophysical Journal, Letters, 508, L95-L98 (1998)
Abstract
We present results from the first three-dimensional calculations
ever to follow the collapse of a molecular cloud core
(~ 10^{-18} g cm^{-3}) to stellar densities
(> 0.01 g cm^{-3}).
The calculations resolve structures over 7 orders of magnitude in
spatial extent (~ 5000 AU - 0.1 R_\odot), and over
17 orders of magnitude in density contrast.
With these calculations,
we consider whether fragmentation to form a close binary stellar
system
can occur during the second collapse phase. We find that, if the
quasistatic core that forms before the second collapse phase is
dynamically
unstable to the growth of non-axisymmetric perturbations, the
angular momentum extracted from the central regions of the
core, via gravitational torques, is sufficient to prevent
fragmentation and the formation of a close binary during
the subsequent second collapse.
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