The Nature of Low T /| W | Dynamical Instabilities in Differentially Rotating Stars
A. L. Watts,Nils Andersson,D. I. Jones;A. L. Watts;Nils Andersson;D. I. Jones;
the astrophysical journal2004Vol. 618pp. L37-L40
189
jones2004thethe
Abstract
Recent numerical simulations indicate the presence of dynamical instabilities of the f-mode in differentially rotating stars even at very low values of T/|W|, the ratio of kinetic to potential energy. In this Letter we argue that these may be shear instabilities that occur when the degree of differential rotation exceeds a critical value and when the f-mode develops a corotation point associated with the presence of a continuous spectrum. Our explanation, which is supported by detailed studies of a simple shell model, offers a straightforward way of understanding all of the key features of these instabilities.