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Turbulence and Cloud Angular Momentum

Published online by Cambridge University Press:  13 May 2016

Andreas Burkert
Affiliation:
Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany
Peter Bodenheimer
Affiliation:
UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA

Abstract

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Numerical models of molecular cloud cores are obtained, with assumed Gaussian random velocity fields that are consistent with moderate turbulence. If the velocity power spectrum is taken to be P(k) ∼ kn, with n = − 4 or −3, then the constructed line-of-sight velocity maps on the plane of the sky show gradients that can be interpreted as rotation. Deduced values of angular velocity, angular momentum, and dimensionless rotational parameter β are consistent with observations. The velocity gradient Ω, of an individual core is not a good indicator of its intrinsic angular momentum J/M. However, the distribution of deduced angular momenta from a large sample of cores with different random velocity fields is close to the distribution of actual angular momenta of these model cores if one assumes J/M = pΩR2 where R is the core radius and p must be determined from a Monte-Carlo study. For centrally condensed cores the standard value of p = 0.4 overestimates the mean intrinsic angular momentum by a factor of 3.

Type
IV. Initial Conditions for Binary Formation and Protobinary Systems
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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