As of this writing, the warmabs package is not included as part of the standard xstar distribution, either within heasoft or as part of standalone xstar. Instead, it must be downloaded and installed separately from the ftp site: ftp://legacy.gsfc.nasa.gov/software/plasma_codes/xstar/warmabs22.tar.gz
The contents of the tarfile include:
atdbwarmabs.fits - xstar atomic database binary fits file. This must reside in directory pointed to by the WARMABS_DATA environment variable. This file has the same format as the atdb.fits file used by xstar, but is kept distinct. This is important because the structure of the populations files (described below) depend on the version of the atomic data used in the run which created them. Thus warmabs must use the appropriate version of this data file, the one included in its distribution. The version of atdb.fits used by the headas or xstar installation may not be identical.
coheatwarmabs.dat - compton heating/cooling data file. This must reside in directory pointed to by WARMABS_DATA environment variable. This file is identical to the file coheat.dat which is part of xstar.
fphotems.f - source code for warmabs, photemis, windabs, multabs, hotemis, and hotabs
lmodel_warmabs.dat - local model definition file needed by xspec. When using xspec11, must be renamed to lmodel.dat or catted onto existing lmodel.dat
pops.fits.nxx binary fits files containing pre-calculated level populations for use with the warmabs or photemis model. Currently the user chooses which of these to use using the WARMABS_POP environment variable, eg., by doing 'setenv WARMABS_POP pops.fits.n4' (note that the full path is not used here, rather the path relative to the WARMABS_DATA path).
popshot.fi - binary fits file containing pre-calculated level populations for the hotabs and hotemis models. This file also must reside in directory pointed to by WARMABS_DATA environment variable. This file is not intended for modification by the user
instructions.txt - text version of the xspec11 manual page describing the setup of analytic models
xautosav.xcm - sample xspec script file showing use of model.
README - this file