[mesa-users] MESA opacity tables

[Jason Wright]

Hi, all.  I'm teaching stellar evolution at Penn State and we're using
MESA.  We're coding up our own 1D stellar models, and comparing to the
"right" answers in MESA.

My first big issue is the opacity tables.

My main purpose is to read the tables myself to reproduce the opacities
reported in the logfile for a stellar evolution run.

My reading of the documentation is that the kap preprocessor takes the
tables in the kap_input_data tarball, uses the inlist to decide which are
needed, then blends and combines them into a MESA formatted table in the
data/kap_data/ directory.  The notes in the kap/ directory state that:

file header (first 3 lines) of gn93_z2m2_x70.data

fixed metal distribution -- based on Grevesse & Noels (1993) solar
abundances
    form     version        X           Z          logRs    logR_min
 logR_max       logTs    logT_min    logT_max
       1          19    0.700000    0.020000          33   -8.000000
 8.000000         142    2.700000    9.300000

which, based on the logT range, looks like a combination of the Wichita,
OPAL, and higher T tables, which is what I want.  But that's not what I
have in mine:

 > head -3 data/kap_data/gn93_z2m2_x70.data
fixed metal distribution -- based on Grevesse & Noels (1993) solar
abundances
    form     version        X           Z          logRs    logR_min
 logR_max       logTs    logT_min    logT_max
       1          37    0.700000    0.020000          37   -8.000000
 1.000000         138    3.750000    8.700000

The minimum logT is 3.75, not 2.7.  It looks like this is just the OPAL
tables, and that the Furgeson tables are not included.

I'm using the default install.

This really confuses me, because MESA runs a 1-solar mass model fine, but
when I compare the output opacities in the logfile to those I compute by
interpolating that file myself, there is a 10% discrepancy for temperatures
below logT=4, which smells like a lack of blending into the Wichita
tables.  So it seems like MESA is using a blended table at runtime, but I
can't seem to find that table in the mesa directories.

Also (and this isn't important to what I'm trying to do, but illustrates
some of my difficulty), I've tried to recompile the opacities using the
scripts in the preprocessor, but run into these errors:

 > ./rn_test inlist
 data/kap_data/lowT_fa05_a09_aFe_p3_z2m2_x95.data
                                               bad logK
 9.4999999999999996D-01    2.0000000000000000D-02    2.7000000000000002D+00
  -1.7899999999999999D+01    1.0000000000000027D-08
 5.0118723362727242D-04
STOP 1

>  ./rn_all
using inlist_a05+Ne

Doing fixed Z = 0.0000
 data/kap_data/a05+Ne_z0m0_x00.data
At line 922 of file ../src/opal_type1.f (unit = 2, file =
'kap_input_data/opal/A05+Ne')
Fortran runtime error: End of file

> file kap_input_data/opal/A05+Ne
opal/A05+Ne: empty

Thanks for any help to get me going...
-- 
                                                -
---------------
Jason T Wright
Assistant Professor of Astronomy
525 Davey Lab
The Pennsylvania State University
University Park, PA 16802
http://exoplanets.org
http://astro.psu.edu/~jtwright/
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