Phase segregation in a two-phase self-gravitating gas mixture

摘要

We discuss the stability of a self-gravitating two-phase gas mixture by linear analysis. The mixture is composed of diffuse phase and immersed dense clouds in pressure equilibrium. Earlier we have shown that in a two-phase self-gravitating mixture, two fundamental wave models are relevant: (1) the gravita- tionally modified sound mode with the intrinsic Jeans length λ_J1 and (2) the modified void (or pattern formation) mode with the Jeans length λ_J2. In this paper, we describe the effect of stabilization of perturbations in a two-phase self-gravitating Mixture: when the diffuse phase dominates in volume(the volume filling factor α≌1), the pattern forma- Tion mode is gravitationally unstable for λ> λ_cr, while the fast acoustic mode remains gravitationally stable for arbitrary λ; when the dense phase dominates(α 1), the slow acoustic mode is gravitationally unstable, while the fast pattern formation mode is stable.