The Surface Density Distribution in the Solar Nebula

The commonly used minimum-mass power-law representation of the early solar nebula is reanalyzed using a new cumulative mass model. This model is a first integral of the planetary data and predicts a smoother surface density approximation compared with methods based on direct computation of surface density. The density is quantified using two independent analytical formulations. First, a best-fit transcendental function is applied directly to the basic planetary data. Next, a solution to the time-dependent disk evolution equation is parametrically adapted to the solar nebula data. The latter model is shown to be a good approximation to the finite-size early solar nebula and, by extension, to extrasolar protoplanetary disks.