Effects of C_d and C_h on the spiral-in curves, a_orb, and the envelope-ejection fraction, f_ej. In panel a the heating parameter is held constant at C_h = 4.00 and the drag-force parameter, C_d, is varied. In panel b the drag-force parameter is held constant at C_d = 0.23 and the heating parameter, C_h, is varied. The thick black lines in both panels show the results from the 3D hydrodynamic CE simulation of Sand et al. (2020), which are shifted by Δt_min = −58 d, the time shift determined using the best-fitting 1D simulation with C_d = 0.23 and C_h = 4.00.