Nonlinear Instability in Gravitational Euler-Poisson system for   $\gamma={6/5}$
  The dynamics of gaseous stars can be described by the Euler-Poisson system. Inspired by Rein's stability result for $\gamma>{4/3}$, we prove the nonlinear instability of steady states for the adiabatic exponent $\gamma={6/5}$ in spherically symmetric and isentropic motion. 
Juhi Jang