Authors: Kathryn Z Hadley William Dumas James N Imamura Erik Keever Rebecka Tumblin
Publish Date: 2015/08/04
Volume: 359, Issue: 1, Pages: 10-
Abstract
We follow the development of nonaxisymmetric instabilities of selfgravitating disks from the linear regime to the nonlinear regime Particular attention is paid to comparison of nonlinear simulation results with previous linear and quasilinear modeling results to study the mass and angular momentum transport driven by nonaxisymmetric disk instabilities Systems with startodisk mass ratios of M /M d = 01 and 5 and innertoouter disk radius ratios of r /r + = 047 to 066 are investigated In disks where selfgravity is important systems with small M /M d and large r /r + Jeanslike J modes are dominant and the gravitational stress drives angular momentum transport In disks where selfgravity is weak systems with large M /M d and large r /r + sheardriven P modes dominate and the Reynolds stress drives angular momentum transport In disks where selfgravity is intermediate in strength between disks where P modes dominate and disks where J modes dominate I modes control the evolution of the system and the Reynolds and gravitational stresses both play important roles in the angular momentum transport In all cases redistribution of angular momentum takes place on the characteristic disk timescale defined as the orbital period at the location of maximum density in the disk midplane The disk susceptible to onearmed modes behaves differently than disks dominated by multiarmed spirals Coupling between the star and the disk driven by onearmed modes leads to angular momentum transfer between the star and disk even when instability is in the linear regime All modes drive spreading of the disk material and eventually accretion onto the star The disks dominated by an I mode and onearmed mode do not lead to prompt fission or fragmentation The J mode dominated disk fragments after instability developsThe authors thank an anonymous referee for a careful reading of an earlier version of this manuscript The referee’s thoughtful comments and helpful suggestions led to a substantial improvement of the manuscript The authors also thank the National Science Foundation and the National Aeronautics and Space Administration for support The computations were supported by a Major Research Instrumentation grant from the National Science Foundation Office of Cyber Infrastructure “MRIR2 Acquisition of an Applied Computational Instrument for Scientific Synthesis ACISS” Grant Number OCI0960534 JNI thanks Kobe University and host Dr Masayuki Itoh for support and hospitality during which a portion of this research was carried out
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