Envelope Structure¶

TODO: Missing velocity structure (i.e. radially infalling, disk Keplerian)

Please take a look at Rab+ 2017 where the implementation of the envelope structure is described in detail. Please also cite this paper if you use the envelope mode for a publication.

You can find a full example for an envelope model in the examples folder of ProDiMo here: examples/StandardObjects/ClassI

Setup¶

Here is an example for a disk plus envelope setup for a typical Late Class I Source:

------ Envelope -----------
.true.        ! env_structure     activates the envelope mode
5000.0        ! Rout              [AU] the outer radius of the whole structure
125.0         ! env_Rcent         Centrifgual radius required for the calculation of the envelope structure
                                  should be similar to Rtaper for the disk
0.4           ! env_Rcavity       [AU] this is where the envelope structure stars (distance from the star)
1d-6          ! env_Mdot          accretion rate for the envelope (defines the mass of the envelope)
1.07          ! env_cav_pow       these two parameters are for the shape (concave) of the outflow cavity
1.0           ! env_cav_coef
1.0           ! env_amax          the maximum dust grain size in the envelope (optional)
60.0          ! beta_max          this value depends on the size of the outflow cavity somebody wants (opening angle).
                                  this also defines the border of the grid in z-direction

For the envelope density structure we use the density structure for the rotationally flattened infalling envelope model (see e.g. Whitney+ 2003, McKee+ 2003).

The disk parameters work the same as in the disk only mode. The outer radius of the disk can be controlled by the paramters Rtaper and gtaper. The envelope structure is simply added on top of the disk structure. The transition from the disk to the envelope is defined by the code in the following way:

• the disk and envelope density structures are calculated independently for the whole model space
• for each grid point the code compares the density of the envelope and the disk
• if the density of the envelope is larger than the density of the disk, the grid point is marked as envelope point

Dust properties¶

The parameter env_amax sets the maximum grains size in the envelope structure (for all points which are marked as envelope). This allows to have different dust populations for the disk and envelope. However, currently only the maximum grain size can be changed, all other dust properties are the same for the disk and envelope.

For the moment it is not possible to use dust settling in the disk if the envelope mode is activated.

Plotting¶

In principle, the plotting tools provided by ProDiMo can also be used for the disk+envelope mode. However, due to the much larger structure, most plots which are fine for disk-only models probably look strange for the envelope models.

prodimopy has somewhat more flexibility than the idl scripts and is therefore better suited for plotting envelop models.

Here are some (rather old) example plots for a structure with disk plus envelope: