Radiation pressure efficiency (β_rp) for grains around HD 15407 A as a function of grain size s for amorphous MgFeSiO₄ (solid black), MgFeSi₂O₆ (red dashed), MgSiO₃ (blue dotted), Mg₂SiO₄ grains (green dotted-dashed), crystalline Mg-rich and Fe-rich olivine grains (solid magenta, and dashed cyan) and β-cristobalite grains (dashed black). Shaded areas show regions where grains are gravitationally unbound to the star.