Hydrodynamic attractor in a Hubble expansion

We analytically investigate hydrodynamic attractor solutions in both M\"{u}ller-Israel-Stewart (MIS) and kinetic theories a viscous fluid system undergoing Hubble expansion with fixed rate. show that the gradient for MIS theory Chapman-Enskog Boltzmann equation within relaxation time approximation are factorially divergent obtain by applying Borel resummation technique to those asymptotic series. In theories, we find globally attractive only first-order non-hydrodynamic mode exists. also two disagree each other when gradients become large, speed of attraction is different. Similarities differences from attractors Bjorken Gubser flows discussed. Our results push idea far-from-equilibrium hydrodynamics systems expansion.