We study the asymptotic profiles, uniqueness and orbital stability of MCCANN’s uniformly rotating binary stars (Houston J Math 32(2):603–631, 2006) governed by the Euler–Poisson system. A new uniqueness result will be importantly used in stability analysis. Moreover, we apply our framework to the study of uniformly rotating binary galaxies of the Vlasov–Poisson system through REIN’s reduction (Handbook of differential equations: evolutionary equations, vol III, pp 383–476, 2007).