Radiative Transfer in Dusty Circumstellar Disks and Envelopes
One of the most important tools for my research is a continuum radiative transfer package
called RADMC. This is a Monte Carlo code that can compute the transport of continuum
radiation through an axisymmetric dusty medium surrounding a star. I also developed
other radiative transfer tools, such as a program called RADICAL that can do
various types of radiative transfer including non-LTE molecular line transfer.
However, this program is old and will be phased out. Instead, to replace both RADMC and
RADICAL, I am currently developing RADMC-3D. This includes dust and line transfer in one
code, has 1-D, 2-D and 3-D capabilities with adaptive mesh refinement (AMR) etc. That will
be our workhorse radiative transfer tool for the future.
Computer programs for radiative transfer
- RADMC: An easy-to-use Monte Carlo radiative transfer code for
axisymmetric dusty media surrounding a star. RADMC is very easy to use.
It is basically plug-and-play, and it is not too sensitive to issues
of gridding (though still care has to be taken).
For most problems of dust continuum radiative
transfer in axisymmetric circumstellar disks and envelopes, this is
the method of choice. See the RADMC web
page. A public domain version of this program will be released
some time in 2008. I apologise to those who have been waiting for
the public code to appear: I was not satisfied with the package
yet, and only recently managed to find time to write a manual for
- RADMC-3D: This is the 3-D version of RADMC. It is a completely
new code, written from scratch though with many of the subroutines
imported from RADMC and from RADICAL. It is much more flexible, has
1-D, 2-D and 3-D capabilities, has adaptive mesh refinement (AMR),
has both dust and line transfer. The first version of the code
is now ready, though lacking a number of important options. But
for a sneak-preview, you can visit the RADMC-3D web page. If you are interested in becoming a beta-tester, please
send me an email.
- RADICAL: A multi-purpose 2-D radiative transfer program for
axi-symmetric circumstellar clouds/envelopes/disks. It can do
dust-continuum transfer as well as gas line transfer. This is an old
code which is now rarely used. We will use RADMC-3D instead in the
- TRANSPHERE-1D (V3): A dust continuum radiative transfer code for 1-D
spherically symmetric circumstellar envelopes. The code is special
in that it can cope with arbitrary optical depths without difficulty,
using the method of Variable Eddington Factors.
It converges within about 10 to 15 iteration (independent of tau)
and has flux conservation usually within the percent level. It is
specially well suited for high optical depth circumstellar envelopes
/ winds around e.g. OHIR stars and Class 0 protostars, but can be
used for any application in which 1-D continuum radiative transfer
is necessary, be it at low, intermediate or high optical depth. A
scaled-down version of this program can be
downloaded here. Note that this is Version-3 of the code. It now
can also handle starless cores with an external interstellar
Author: C.P. Dullemond
- DISKSTRUCT: The diskstruct code also has a 1-D variable
eddington factor radiative transfer code inside. See diskstruct below.
Computer programs for models of passive circumstellar disks
- CGPLUS: A simple Chiang & Goldreich model program for
computing the SED of a flared irradiated passive circumstellar
dust+gas disk. It includes all the additional elements of the
model as discussed in the paper by Dullemond, Dominik & Natta (2001),
for instance: the inner rim, the shadowing and a more consistent
energy conserving treatment of the flared disk.
The program is fast (it computes a model in a few
seconds in the IDL version of the program). A sophisticated
IDL widget interface makes it a very easy-to-use program. This
interface displays the observed SED with the current model fit
overplotted. Parameters can be adjusted on the fly using the
input widgets, and a new model is computed. One can zoom in,
plot in different forms (e.g.lin/log), and save/load the latest
Download it here. NOTE: This model is evidently
highly limited in its realism. Multi-dimensional radiative
transfer codes are better!!
- DISKSTRUCT: The diskstruct code package is the set of programs
used for the papers Dullemond, van Zadelhoff and Natta (2002) A&A 389, 464,
Dullemond & Natta (2003) A&A 405, 597, and Dullemond & Natta (2003) A&A 408, 161.
These programs compute 1+1D disk structure models. The vertical
radiative transfer is a detailed frequency-dependent radiative transfer
calculation using variable eddington factor method (very similar to
that of the TRANSPHERE code above, but now for 1-D vertical plane
parallel problems instead of spherically symmetric problems).
The codes are not very well documented, but there is a README_MANUAL file
with the very basics of the code package. The rest will be up to the
user to figure out. There IS, however, an example model which should
work, and which could give the user a reasonable starting point.
I refer to the above papers for details of the methods etc. You can
download a beta (!!) release, but please keep in mind that it really
IS a beta release, so beware of strange results. Everything is the
responsibility of the user... You can download
the zip package of
the April 2009 release here or you can download
the zip package of
the August 2010 release here. The newest version (August 2010)
has only a few minor improvements over the older one.
- RADMC: The above listed RADMC code is also specialized
in making ready-to-use disk structure models.
Some model results for downloading
For a long time these pages were simply lost (unlinked). This was just a
mistake. So here are some results:
- The flaring and self-shadowing disks of the Dullemond and Dominik
2004a paper can be found here.
- The disk models of Dullemond, van Zadelhoff and Natta 2003
can be found here.
- A little benchmark test for 1-D vertical disk models can be
Last update: August, 2010