Dependence of the planet-induced gas flow on the planetary mass at the midplane. We set ℳ_hw = 0 in all panels. The results were obtained from m005-hw0 (panel a), m01-hw0 (panel b), m05-hw0 (panel c), and m07-hw0 (panel d). The solid thin gray lines are gas streamlines. The solid and thick dashed gray lines are the widest horseshoe streamline and the shear streamline passing closest to the planet, respectively (Appendix E). The color contour represents the flow speed in the x-direction. The dashed and dashed-dotted black circles denote the atmospheric radius (Eq. (5)) and twice the atmospheric radius, where the outflow speed is measured. The dashed blue lines are the curves representing the fitting formula for the critical recycling streamline (Eq. (11); Sect. 3.2.1). The vertical lines are the asymptotes of Eq. (11), representing the extent of the outflow region in the x-direction ((Eq. (17)); Sect. 3.2.2). The horizontal lines denote the y-coordinates of the characteristic length of the outflow region in the y-direction ((Eq. (18)); Sect. 3.2.3).