Instability in the nebula model of compressive viscous gases.

The Jeans instability is a key concept that facilitates our understanding of galaxy and star formation in astrophysics. To understand this dynamics, we consider the dynamics of the three-dimensional compressible Navier–Stokes–Poisson system. We extract the reduction equations using the center manifold theory and analyze its bifurcation structure. Consequently, we obtain solutions corresponding to the growth mode, a symmetric pattern, and a layer pattern on the center manifold of class C 2. These solutions are selected according to the thermal state of the gas. • The Jeans instability for compressible viscous gases is controlled by the Mach number. • The dynamics of the Jeans instability depends on thermodynamic state. • The viscosity of gases does not affect the local dynamics of instability essentially. • Exponential growth, symmetric pattern and layer pattern appear. [ABSTRACT FROM AUTHOR]