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        "Stellar Interiors," 2nd ed, by Hansen, Kawaler, & Trimble
The FORTRAN program WD.FOR computes zero-temperature electron white dwarf
models using the physics of Chapter 3. It integrates the mass and hydrostatic
equations using the full treatment of degeneracy. We have followed
Chandrasekhar, "Introduction to Stellar Structure," Chapter XI in setting
up the problem. The dependent variable is y, which is related to the degeneracy
parameter x by y**2=x**2+1. This is scaled by y_0 (y at r=0) to yield
the new dependent variable  phi=y/y_0. The independent variable is radius r
that appears as the dimensionless variable  eta (and see Chandra for the
scaling constant).
        The way to work this code is to specify rho_0 (the central density
in g/cm**3) and amue (otherwise known as mu_e in the text). The code then
(hopefully) does the rest.
        After you do the above, the code integrates the structure equations
while iterating on an eigenvalue, which the code makes a first guess for.
When converged, it will write to a file of your choosing, and to the screen,
the total radius and mass (both in solar units). The file will also list the
mass (M_r) as a function of radius r. You might compare your results with that
of Fig 3.7 of the text. The sample output given here is for rho_0=10**6 with
mu_e=2 (as in pure helium or carbon).

Note that some of you will have to make the trivial change from .for to .f
for UNIX systems.
        The directory also contains an executable file for WINDOWS based PCs
(WD.EXE) and sample output (WD.OUT). Carl Hansen, Sept 03