Disk Envelopes

As mentioned earlier, density structure is one of the first and primary inputs for the model. The density profiles are inspired by Lyndell-Bell and Pringle for disks, and Ulrich for envelopes.

For envelopes, the model allows for the use of a simple radial profile of gas density given by:

where is the radial co-ordinate in the spherical co-ordinate system, is the characteristic radius at which one has the density known and is the radial power law exponent for envelope density.

The model also has the option of choosing a more physical envelope gas density structure, which is derived from an in-falling rotating envelope model, given by:

where is the gas density parameter of the envelope; is the centrifugal radius of the in-falling envelope; is the cosine of the polar co-ordinate in the spherical co-ordinate system and is the value of as .