XSTAR Model: Spherical cloud

In this example we model a spherical, constant density cloud with a source at its center. The cloud is optically thin. The source luminosity is 10$^{28}$ erg s$^{-1}$. The ionization parameter at the inner edge of the cloud is log($\xi$)=5. The ionizing spectrum is a power law with energy index -1. We show how this model can be run in two ways: first by invoking XSTAR with no parameter values and utilizing the prompting for parameter values from XPI, and second by entering parameter values directly on the command line. In the former case, the prompt strings are more descriptive than the parameter values themselves, but the net result is the same in both cases.

Using prompting:

unix > xstar
 xstar version 2.1
covering fraction (0.:1.) [1.] 
temperature (/10**4K) (0.:1.e4) [100.] 1000.
constant pressure switch (1=yes, 0=no) (0:1) [0] 
pressure (dyne/cm**2) (0.:1.) [0.03] 
density (cm**-3) (0.:1.e18) [1.E+12] 1.e+4
spectrum type?[pow] pow
radiation temperature or alpha?[-1.] -1.
luminosity (/10**38 erg/s) (0.:1.e10) [1.e-10] 
column density (cm**-2) (0.:1.e25) [1.E17] 
log(ionization parameter) (erg cm/s) (-10.:+10.) [2.] 5.
hydrogen abundance (0.:100.) [1.] 
helium abundance (0.:100.) [1.] 
carbon abundance (0.:100.) [1.] 
nitrogen abundance (0.:100.) [1.] 
oxygen abundance (0.:100.) [1.] 
neon abundance (0.:100.) [1.] 
magnesium abundance (0.:100.) [1.] 
silicon abundance (0.:100.) [1.] 
sulfur abundance (0.:100.) [1.] 
argon abundance (0.:100.) [1.] 
calcium abundance (0.:100.) [1.] 
iron abundance (0.:100.) [1.] 
nickel abundance (0.:100.) [0.] 
Courant multiplier (1.e-6:1.e+6) [0.5] 0.5
model name[xstar Default] spherical cloud

Using the command line:

xstar cfrac=1. temperature=1000. pressure=0.03 density=1.e+4 spectrum='pow'  
trad=-1. rlrad38=1.e-10  column=1.e+17   rlogxi=5.  lcpres=0 habund=1. heabund=1.  
cabund=1. nabund=1. oabund=1. neabund=1. mgabund=1. siabund=1.  sabund=1.  
arabund=1. caabund=1. feabund=1. niabund=0. niter=99 modelname="spherical cloud"