Comparison of giant impacts among atmosphereless super-Earths to collisions involving atmosphere-rich targets. (a) Density of the surviving hit-and-run projectile, ρ_S, as a function of v_coll. The value of ρ_S is plotted in units of $\overline{\rho }$, which is the density of a planet with the same R and a bulk composition with the average local galactic abundance of iron and rock-forming elements. We assume θ = 45°. The predictions for the Sub-Neptune target are from the database of SPH simulations by Denman et al. (2022). The predictions for the super-Earth target are from our collision model described in Section 2.2.3. (b) Minimum impact angle, θ_g, required for the geometric center of a projectile to graze the surface of its target [Equation (9) in Asphaug 2010] as a function of their projectile-to-target radius ratio, R_P/R_T . A super-Earth with R_P = 1.5 R_⊕ grazes a Jupiter-sized planet (R_T = 11.2 R_⊕) for θ > θ_g = 60°. By contrast, if the target is a super-Earth with R_T = 2 R_P, θ_g is within 5° of the most probable impact angle of 45°.