Radius of the orbiting star and impact parameter β = r_t/r_p as a function of the stellar mass. The allowed regions were computed based on fitting formulae in Guillochon & Ramirez-Ruiz (2013 and related errata corrige). Upper panel: orbiting stars characterised by a polytropic index γ = 4/3. The red region in the lower panel shows the allowed β parameters. The light red region approximately excludes the low-mass end (≲1 M_⊙) and the stars more evolved than the giant branch because they are not well described by a polytropic index γ = 4/3. Orange dots indicate stars in the main -sequence phase, yellow dots the Hertzsprung gap, black dots the giant branch, light blue dots the helium core-burning, and blue dots the asymptotic giant branch phase. Lower panel: polytropic star with index γ = 5/3. Colours, dots, and regions are as above. The light red region approximately excludes the high-mass end (≳1 M_⊙), because these stars are not well described by a polytropic index γ = 5/3 (but includes evolved giant stars). No acceptable solutions remain for this case.