Orbit-crossing time t_X of 0.3 M_⊕ embryos assembled at a ∼ 1 au with eccentricity e = 0.001, as a function of orbital spacing k. The eccentricity-damping timescales t_damp of the embryos in a gaseous nebula depleted by factors f_dep = [10⁻², 10⁻³, 10⁻⁴] are displayed with cyan, yellow, and magenta dashed horizontal lines, respectively. The damping times are multiplied by 10 to assess the merger criterion t_X < 10t_damp of J. C. B. Papaloizou & J. D. Larwood (2000). As a reference, the orbital spacing k_E−V between the Earth and its nearest neighbor Venus is indicated with a red dotted vertical line.