Abstract
We examine the conditions under which binary and multiple stars may form out
of turbulent molecular cloud cores using high resolution 3-D, adaptive mesh
refinement (AMR) hydrodynamics (Truelove et al., 1997, 1998; Klein, 1999). We
argue that previous conclusions on the conditions for cloud fragmentation have
limited applicability, since they did not allow for the nonlinear density and
velocity perturbations that are ubiquitous in molecular cloud cores. Over the
past year, we have begun to simulate the evolution of marginally stable,
turbulent cores. These models have radii, masses, density contrasts, turbulent
linewidths, and projected velocity gradients consistent with observations of
low-mass molecular cloud cores. Our models are evolved in time under
self-gravitational hydrodynamics with AMR using a barotropic equation of state
that models the transition from an isothermal to an adiabatic equation of
state. We examine several properties of the resulting protostellar fragments
and discuss the qualitative nature of the fragmentation process in realistic
cloud cores: the transition from single to binary and multiple stars; the
formation of misaligned binary systems; and the role played by filament
formation in the formation of stars.