Stellar continua in C06.02 and before

Preparing the Rauch stellar atmospheres

Obtain the tar files from Thomas Rauch’s  Web site.

There are “first generation” and “second generation” grids available. The second generation gives a better representation of the opacity effects of heavy elements, but does not extend to as high a temperature as the first generation. The second generation is used by default, although it is possible to also use the first generation. Each generation also has two abundance sets, halo and solar.

'Second generation'. The link given above points to the top level for all the stellar atmospheres. You want the “second generation H-Ni” set. Click on the “H-Ni” link. At the bottom of the page you will find two sets of atmospheres. You want the solar and halo abundances dated July 2002 and June 2002 respectively. The general format for each atmosphere is temperature_gravity_abundances.bin_0.1.

'First generation'. This set is not necessary, but can be used if desired. The link given above points to the top level for all the stellar atmospheres. You want the “first generation H-Ca” set. Click on the “H-Ca” link. At the bottom of the page you will find several sets of atmospheres. You want two sets of files, for solar and halo abundances. These are dated Feb 1998 and May 1998 respectively, and have a note that says that they are for versions 90.05 and later. The general format for each atmosphere is temperature_gravity_abundances.wf.

'Both generations'. Uncompress and explode these tar files into a subdirectory. This will create a large number of stellar atmosphere files with names ending with the extension “.wf” (the first generation) and “bin_0.1” (the second generation). Next execute Cloudy with the single command

compile stars Rauch initialize

to compile the second generation files. This will create the files rauch02_halo.ascii and rauch02_solar.ascii that are needed for the final step. Only these two files need be retained. If you also want to use the first generation grid you will also need to execute the code with the single command

compile stars old Rauch initialize

This will create the files rauch_halo.ascii and rauch_solar.ascii that are needed for the final step.

Obtain the CoStar spectra

These are developed by Daniel Schaerer and are described in Schaerer et al. (1996ab) and Schaerer & de Koter (1997). There are two abundance sets, halo and solar. They are available on the web from  here - you want the files Sc1_costar_z020_lb.fluxes (solar abundances) and Sc1_costar_z004_lb.fluxes (halo metallicity).

Werner and Kurucz star files

The three files werner.ascii, kurucz.list, and kurucz.ascii files come directly from  the Cloudy ftp site.

The final set of ASCII files

At this stage the files you have are the following ASCII files:

Sc1_costar_z020_lb.fluxes and Sc1_costar_z004_lb.fluxes These are the set of CoStar stellar atmospheres.

werner.ascii This is a plain ASCII version of the Werner and Heber (1991) grid of hot stellar atmospheres. These data extend from 1e-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 a subset of the 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 1.6e5 nm (5.7e-4 Ryd).

rauch02_halo.ascii and rauch02_solar.ascii These are the sets of second generation Rauch hot stellar atmospheres as created and described in the section "Preparing the Rauch stellar atmospheres" above.

rauch_halo.ascii and rauch_solar.ascii These are the sets of first generation “old” Rauch hot stellar atmospheres that were described above. These first generation grids lack the opacities from iron-group elements, but can be useful since they extend to higher temperatures.

Compiling the star files

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 workstation.

This does not compile the first generation Rauch stars. If you want to use them it is also necessary to execute the code one time with the command compile stars only old Rauch as input.

The final files

Six direct access files, atlas.mod, rauch02_halo.mod, rauch02_solar.mod, costar_sol.mod, costar_halo.mod, and werner.mod will be created. Additionally the files rauch_halo.mod, rauch_solar.mod will be created if the first generation Rauch atmospheres are needed. These are the files that Cloudy must access to use the table star continua.

Using the stellar atmospheres

The location of the code’s data files was specified by entering the path in the file path.c as described on page 30 below before creating the Cloudy executable. The “*.mod” files should be located in this data directory. The table stars command will then function normally.

The code will stop if it cannot locate the *.mod file when the corresponding table stars command is entered. The code also checks that the energy grid in the compiled data file agrees with that in the code itself to confirm that the star files are appropriate for the current version of Cloudy. As a result it is generally necessary to recompile the stars files when the code is updated.

Cleaning up after compilation

Only the *.mod files are needed to compute simulations. The *.ascii files and the *.wf atmosphere files can be deleted or compressed. They will only be needed again if the continuum mesh within the code is changed. If this happens then it will be necessary to recompile the binary files. The Rauch *.wf files will never be needed again, unless one of the atmospheres is updated and it is necessary to recreate this set.

If the continuum binning is changed

The continuum resolution is specified by the contents of the file continuum_mesh.dat, which lives in the data directory. That file describes how to change the resolution. If the continuum binning is changed then it will be necessary to recompile the star files, using the compile stars command.

Compiling only one set of stars

compile stars only - -. You may not need all of the stellar atmospheres. The keyword only followed by one of the keywords Rauch, Atlas, CoStar, or Werner will only compile that set of stellar atmospheres.


Running the TestSuite is the next step

Return to the CompileStars page

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