[mesa-users] Adding heavier elements to initial composition

[Aaron Dotter]

Hi Leonardo,

In order to include the abudance of a particular isotope in a MESA model,
that isotope must be in the nuclear network.  There are lots of these
predefined (and it's straightforward to roll your own).  See
mesa/data/net_data/NET_NOTES and mesa/data/net_data/nets/ for the existing
networks.

After you sort out the net you'd like to use, you can specify the initial
composition for that net at the beginning of a run using these options from
the star_job inlist:

     ! the following is an alternative to the above
"set_uniform_initial_composition" method.
      file_for_uniform_xa = ''
      set_uniform_initial_xa_from_file = .false.
      set_uniform_xa_from_file = .false.
         ! if true, read list of (iso name, mass fraction) pairs from file
file_for_uniform_xa
         ! and use them to set uniform composition

The xa file should have one line per isotope in the net, which gives the
name of the isotope and the mass fraction (make sure they sum to 1!).  For
example, I have used these in a file with the basic network:

> cat initial.abund
  h1    7.46340778E-01
 he3    4.18748232E-05
 he4    2.52257971E-01
 c12    2.33923100E-04
 n14    6.85233075E-05
 o16    6.36218344E-04
ne20    1.45556640E-04
mg24    2.75154264E-04



Aaron
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