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Fragmentation and Star Formation in Turbulent Cores

Published online by Cambridge University Press:  13 May 2016

Richard I. Klein
Affiliation:
University of California, Lawrence Livermore National Laboratory and Berkeley Department of Astronomy, 601 Campbell Hall, Berkeley, California, 95720
Robert Fisher
Affiliation:
University of California, Berkeley, Department of Physics
Christopher F. McKee
Affiliation:
University of California, Berkeley, Department of Physics

Abstract

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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 proto-stellar 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.

Type
IX. Theoretical Context - Detailed Calculations
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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