Dependence of the cooling rates computed from models with different values of (from 10² to 10⁵ Mm^-1 cm³ g^-1) and k_z (=1, 2, and 4 indicated by diamonds, triangles, and squares, respectively). 2D models with four and eight rays are indicated by crosses and circles, respectively, while 3D models with six rays are shown as plus signs. The red solid line corresponds to Eq. (A.5), the dashed blue line to Eq. (A.4), and the dotted line with open circles to the case without correction factor.