Top: radial profiles of the Toomre Q-parameter at 30 kyr (a) and 40 kyr (b) after protostellar birth. The horizontal dashed line marks the threshold value of ﹩\sqrt{3}﹩, below which the gravitational instability develops. Bottom: effective α_GI parameter (c) and Reynolds α_R parameter (d) for the disk. The values of α_GI and α_R are lowest in the innermost regions of the disk and highest near its outer edge, which is outlined by the black line. Note that α_GI and α_R are higher than α_visc throughout most of the disk.