Rossby wave instabilities of protoplanetary discs with cooling

ABSTRACT Rossby wave instabilities (RWIs) usually lead to non-axisymmetric vortices in protoplanetary discs and some observed substructures of these can be explained well by RWIs. We explore how the cooling influences growth rate unstable RWI modes terms linear perturbation analysis. The associated with energy equation is treated two different ways. first approach that we adopt a simple law. perturbed thermal state relaxes initial on prescribed time-scale. In second approach, treat as diffusion process. difference between adiabatic isothermal becomes more pronounced for smaller sound speed. For law, rates monotonically decrease shorter time-scale barotropic discs. However, dependence non-monotonic non-baratopic RWIs might even enhanced non-barotropic during transition from state. When diffusion, discs, variation diffusivity non-monotonic. Furthermore, maximum may appear an appropriate value diffusivity. angular momentum flux investigated understand transport cooling.