Kevin Volk incorporated three large grids of stellar atmosphere continua into Cloudy. The table star atlas, table star Rauch, and table star Werner commands use these. There are two steps involved in preparing the star files for use by Cloudy: first remap the original stellar atmospheres onto the Cloudy grid with the compile stars command, then use these files with the table star commands. The first step is only done once while installing Cloudy.

First obtain the tar file from Thomas Rauch’s Web site, http://astro.uni-tuebingen.de/~rauch/flux.html and obtain the tar file with the complete data set. Uncompress and explode this file in its own subdirectory. This will create 57 stellar atmosphere files with names ending with the extension wf. Next execute Cloudy with the single command

This will create the file rauch.ascii that is needed for the next step. Only this file need be retained.

Four files are needed to prepare to compile the stellar atmospheres, so that they can be used in model calculations. The rauch.ascii file was created above, and the werner.ascii, kurucz.list, and kurucz.ascii files come directly from the Cloudy Web site.

werner.ascii This is a plain ASCII version of the Werner and Heber (1991) grid of hot stellar atmospheres. These data extend from 10^-5 Ryd through 182.25 Ryd.

kurucz.list This is a plain ASCII list of all files in the Kurucz (1991) grid.

kurucz.ascii This is the set of Kurucz (1991) atmospheres. The wavelengths of the grid are stored in nanometers as the first record. These data extend from 9.090 nm (10.0 Ryd) through 1.600´ 10⁵ nm (5.7´ 10^-4 Ryd).

rauch.ascii This is the set of Rauch hot stellar atmospheres, and was created as described in section 1.2.2 above.

When the stars are compiled, as described next, three files, atlas.mod, rauch.mod, and werner.mod, are created.

The stellar atmosphere files are very large, and reading them using Fortran sequential access would be very slow. Direct access is used to read these files in a timely manner. Direct access reads are a part of the ANSII Standard Fortran. Unfortunately the form of the file is machine specific, so that these files are not portable, although the code used to read or write them is portable.

It is necessary to have Cloudy compile the stellar atmosphere files before they can be used. This only needs to be done when the code is first installed, or if the energy mesh is changed. Follow these steps to compile the star files:

• Move the files kurucz.ascii, kurucz.list , rauch.ascii, and werner.ascii (ASCII files obtained from the web site or created above) into the directory where Cloudy lives.
• Execute Cloudy with only the single command compile stars as input. Examine the resulting output for any comments indicating success or failure. I do this with the output coming to the screen so that I can monitor progress. This step typically takes about 15 minutes on my workstations.
• Three direct access files, atlas.mod, rauch.mod, and werner.mod will be created. These are the files which Cloudy must access to use the table star atlas, table star rauch, or table star Werner continua.
• To execute the code from other directories it is necessary to set the path to the directory containing these two files with the set path command described on page * of this document.

When doing later photoionization calculations, the code will stop before computing a model if it cannot locate the atlas.mod, rauch.mod, or werner.mod files when the corresponding table stars command is entered. The code also checks that the energy grids in the star files and the code itself agree, to confirm that the star files are appropriate for the current version of Cloudy.

Only the atlas.mod, rauch.mod, and werner.mod are needed by Cloudy, and they only need to be created one time. The files werner.ascii, kurucz.list, rauch.ascii, kurucz.ascii, and the *.wf atmosphere files can be deleted or compressed after the compilation is complete. They will only be needed again if the continuum binning within the code is changed. The Rauch *.wf files will never be needed again, unless one of the atmospheres is updated and it is necessary to recreate this set.

The call to routine fill can be changed to change the continuum binning or resolution. This is described in a section of Part II of this document. If the continuum binning is changed then it will be necessary to recompile the star files, using the compile stars command, and then change the values of three related variables within the code. During the compilation of the star files the code will note the values of the variables nWerner, nRauch, and nAtlas that must be entered. Block data scalar must be edited to enter these new values where they appear in data statements.