Radial Oscillations of Viscous Stars
The study investigates how viscosity affects radial oscillations in cold, polytropic neutron stars using two hydrodynamic models: Eckart and BDNK. Viscosity damps radial modes on millisecond timescales and shifts oscillation frequencies by up to a percent, increasing with star compactness and viscosity. The research also shows that while viscosity cannot prevent gravitational collapse at the linear level, it significantly slows down the rate of collapse.