Distances from the disk to the interaction region as a function of time are depicted for model M1b, which has only an EUV radiation field: d_d − IR,c (full line) are the calculated distances, where stellar and the photoevaporated wind ram pressures match; d_d − IR,m (dotted-line) are the distances as measured from the simulations (along the x-axis, with y = z = 4.9 × 10¹⁵ cm). The distances are in units of 10¹⁵ cm (left-axis). Also shown is the disk mass loss Ṁ (dashed-line), in units of 10^-8   M_⊙ yr^-1 (right axis). The Ṁ has been calculated by computing the quantity ρA·v on the faces of a cube centered at the disk center, with a = 3r_d.