Show simple item record Michael, S. en Steiman-Cameron, T.Y. en Durisen, R.H. en Boley, A.C. en 2014-10-27T17:12:07Z en 2014-10-27T17:12:07Z en 2012 en
dc.identifier.citation Michael, S., Steiman-Cameron, T. Y., Durisen, R. H., & Boley, A. C. (2012). Convergence studies of mass transport in disks with gravitational instabilities. I. the constant cooling time case. Astrophysical Journal, 746(1). en
dc.description.abstract We conduct a convergence study of a protostellar disk, subject to a constant global cooling time and susceptible to gravitational instabilities (GIs), at a time when heating and cooling are roughly balanced. Our goal is to determine the gravitational torques produced by GIs, the level to which transport can be represented by a simple α-disk formulation, and to examine fragmentation criteria. Four simulations are conducted, identical except for the number of azimuthal computational grid points used. A Fourier decomposition of non-axisymmetric density structures in cos ($m\phi$), sin ($m\phi$) is performed to evaluate the amplitudes $A_{m}$ of these structures. The $A_{m}$, gravitational torques, and the effective Shakura & Sunyaev α arising from gravitational stresses are determined for each resolution. We find nonzero $A_{m}$ for all $m$-values and that $A_{m}$ summed over all $m$ is essentially independent of resolution. Because the number of measurable $m$-values is limited to half the number of azimuthal grid points, higher-resolution simulations have a larger fraction of their total amplitude in higher-order structures. These structures act more locally than lower-order structures. Therefore, as the resolution increases the total gravitational stress decreases as well, leading higher-resolution simulations to experience weaker average gravitational torques than lower-resolution simulations. The effective $\alpha$ also depends upon the magnitude of the stresses, thus $\alpha_{\text{eff}}$ also decreases with increasing resolution. Our converged $\alpha_{\text{eff}}$ is consistent with predictions from an analytic local theory for thin disks by Gammie, but only over many dynamic times when averaged over a substantial volume of the disk. en
dc.language.iso en_US en
dc.publisher The American Astronomical Society en
dc.relation.isversionof en
dc.rights © 2012 The American Astronomical Society. All rights reserved. en
dc.subject accretion en
dc.subject accretion disks en
dc.subject protoplanetary disks en
dc.subject stars: formation en
dc.title Convergence studies of mass transport in disks with gravitational instabilities. I. the constant cooling time case en
dc.type Article en
dc.altmetrics.display false en

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search IUScholarWorks

Advanced Search


My Account