Minimum Mass Solar Nebulae Scaling Factors I'm attempting to build a MMSN, I've been trying for about... a week to get an intuition on the scaling factors for calculating the mass of the disks, I'm not entirely sure how to think about it. I feel as if the concept is extremely simple but that I'm thinking of it incorrectly. Can someone explain what exactly these scaling factors account for and how one would calculate them? I'm not looking for a solution, I'm looking for intuition on how these scaling factors are found. 

My understand is that you pick an element, (Fe), and compare that to the solar abundance (does this mean the abundance of Fe in the sun? From there I would look at the abundance of Fe in the cores of the planet and compare them somehow to get some sort of scaling factor. From what I understand Fe makes .14% of the suns mass, so if I know lets say that neptune has a mass of 17m(earth) how would I start finding the scaling factor. 

Thanks!
Attempt to do an intuitive explanation:

The Sun was formed from a cloud of matter. A small amount of that matter remained around the Sun, and had a similar composition. This was the solar nebulae.

But the composition of the planets are now not the same as the Sun. This is explained by that some of the matter was collected by the Sun, and some of it was blown out of the system.

That was only the light stuff! like hydrogen and helium. Most iron and other metals are conjectured to have remained in orbit, forming the planets.

As the Sun is representative for the original composition (partly at least, stellar fusion has skewed the hydrogen/helium ratio). So if iron is 0.14% of the Sun, that is also the original abundance in the nebulae. So all the iron in the planetary bodies is 0.14% of the original nebulae mass.

From that you can calculate the original mass. It is a 'minimum' because some of the iron may have escaped as well.