Just a Module

This document describes how to use the MESA equation of state, opacity, and nuclear reaction networks outside of MESA.

Download from Zenodo this set of directories and makefiles: Just A Module.
Unpack the zip file anywhere you prefer.

1. Equation of State

Before starting, explore Overview of eos module and eos module controls.
From where you unpacked the zip file
cd my_eos
cp $MESA_DIR/eos/test/src/sample_eos.f90 .

Edit sample_eos.f90 and change the variable

my_mesa_dir = '../..'

to your $MESA_DIR, or use a blank string, in which case your $MESA_DIR is automagically used

my_mesa_dir = ''

while you are editing sample_eos.f90, take some time to explore the source code. Save and exit sample_eos.f90. Now take some time to explore the makefile, and use it to build the executable

make

Run the interactive executable, named sample_eos

./sample_eos
loading eos tables

give the temperature, density, and mass fractions (h1, he4, c12, n14, o16, ne20, mg24) =>
hit return for T = 1e9 K, Rho = 1e9 g/cc, x(c12) = 1 ; enter -1 to stop


T     =  1.000000E+09 Rho   =  1.000000E+04 abar  =  1.200000E+01 zbar  =  6.000000E+00
h1    =  0.000000E+00 he4   =  0.000000E+00 c12   =  1.000000E+00 n14   =  0.000000E+00
o16   =  0.000000E+00 ne20  =  0.000000E+00 mg24  =  0.000000E+00

quantity      value          d/d(Rho)       d/d(T)       d^2/d(Rho)^2   d^2/d(Rho)d(T) d^2/d(T)^2
p tot   =   3.033664E+21   4.616282E+16   1.098950E+13   7.389591E+11  -2.632100E+07   3.148155E+04
p gas   =   5.117530E+20   4.616282E+16   9.018528E+11   7.389591E+11  -2.632100E+07   1.218618E+03
p rad   =   2.521911E+21   0.000000E+00   1.008764E+13   0.000000E+00   0.000000E+00   3.026293E+04

e tot   =   8.606704E+17  -7.955833E+13   3.425527E+09   1.626134E+10  -3.604408E+05   1.309327E+01
e gas   =   1.040971E+17  -3.900997E+12   3.992340E+08   1.129877E+09  -5.781150E+04   4.014391E+00
e rad   =   7.565733E+17  -7.565733E+13   3.026293E+09   1.513147E+10  -3.026293E+05   9.078880E+00

s tot   =   1.476688E+09  -1.098950E+05   3.425527E+00   2.186704E+01  -3.604408E-04   9.667743E-09
s gas   =   4.679233E+08  -9.018528E+03   3.992340E-01   1.691755E+00  -5.781150E-05   3.615157E-09
s rad   =   1.008764E+09  -1.008764E+05   3.026293E+00   2.017529E+01  -3.026293E-04   6.052587E-09

n_ion   =   5.018451E+26   5.018451E+22   0.000000E+00
n_ele   =   3.200158E+27   2.870797E+23   1.414171E+18
eta_e   =  -4.182056E+00   9.451310E-05  -1.319764E-09
cv      =   3.425527E+09  -3.604408E+05   1.309327E+01
cp      =   2.958707E+10  -5.803942E+06   2.045230E+02
gamma_1 =   1.314315E+00   5.192048E-06  -3.807384E-10
gamma_2 =   1.322910E+00   9.783797E-07  -1.079536E-10
gamma_3 =   1.320812E+00   2.002091E-06  -1.740076E-10
grad_ad =   2.440906E-01   5.590452E-07  -6.168458E-11
chi_t   =   3.622516E+00  -5.143301E-05   2.381262E-09
chi_d   =   1.521685E-01   1.443976E-05  -5.143301E-10
c_sound =   6.310334E+08  -2.640054E+04   1.141379E+00

dsp   =  2.220446E-16 dpe   =  7.993606E-15 dsp   = -2.331468E-15

give the temperature, density, and mass fractions (h1, he4, c12, n14, o16, ne20, mg24) =>
hit return for T = 1e9 K, Rho = 1e9 g/cc, x(c12) = 1 ; enter -1 to stop

-1
STOP normal termination

For homework, edit sample_eos.f90 to write out \(\partial{T}/\partial{\rho}|_{S}\). As mentioned in sample_eos.f90, it can be useful to look at the integer indices contained in $MESA_DIR/eos/public/eos_def.f90.

2. Opacity

Before starting, explore Overview of kap module and kap module controls.
From where you unpacked the zip file
cd my_kap
cp $MESA_DIR/kap/test/src/sample_kap.f90 .
cp $MESA_DIR/kap/test/sample_kap_agb.model .

Edit sample_kap.f90 and change the variable

my_mesa_dir = '../..'

to your $MESA_DIR, or use a blank string, in which case your $MESA_DIR is automagically used

my_mesa_dir = ''

while you are editing sample_kap.f90, take some time to explore the source code. Save and exit sample_kap.f90. Now take some time to explore the makefile, and use it to build the executable

make

Run the executable, named sample_kap, which reads a mesa model file and writes out the opacity and its derivatives at each cell

./sample_kap
 Npts        1331
Nspec          31

Z_init   1.0000000000000000E-002

write kap_test.data

Explore the output with, for example,

head -4 kap_test.data
                       grid                     log_T                    log_Rho                      kappa                   kappa_CO                dlnK_dlnRho                  dlnK_dlnT
                          1   3.5585465937700458E+000   -8.4473997504616456E+000    1.7963661540128417E-003    1.7963661540128417E-003    5.9324713626960102E-001    7.7443291473465914E+000
                          2   3.5585885995787634E+000   -8.4471065383083204E+000    1.7984321714713182E-003    1.7984321714713182E-003    5.9331124051888307E-001    7.7411914141868570E+000
                          3   3.5586446634268447E+000   -8.4467158120772723E+000    1.8011910725944315E-003    1.8011910725944315E-003    5.9339708647788947E-001    7.7370154334784580E+000

3. Nuclear Reaction Networks

Before starting, explore Overview of net module and Reaction Networks.
From where you unpacked the zip file
cd my_net
cp $MESA_DIR/net/test/src/sample_net.f90 .

Edit sample_net.f90 and change the variable

my_mesa_dir = '../..'

to your $MESA_DIR, or use a blank string, in which case your $MESA_DIR is automagically used

my_mesa_dir = ''

while you are editing sample_net.f90, take some time to explore the source code. Save and exit sample_net.f90. Now take some time to explore the makefile, and use it to build the executable

make

Run the interactive executable, named sample_net

./sample_net

load approx21.net

give the temperature, density, and mass fractions (h1, he4, c12, n14, o16, ne20, mg24) =>
hit return for T = 1e9 K, Rho = 1e4 g/cc, x(c12) = 1 ; enter -1 to stop


T     =  1.000000E+09 Rho   =  1.000000E+04 abar  =  1.200000E+01 zbar  =  6.000000E+00
h1    =  0.000000E+00 he4   =  0.000000E+00 c12   =  1.000000E+00 n14   =  0.000000E+00
o16   =  0.000000E+00 ne20  =  0.000000E+00 mg24  =  0.000000E+00

d(h1)/dt   =  0.000000E+00  d(he4)/dt  =  5.582829E-09    d(c12)/dt  = -3.349697E-08    d(n14)/dt  =  0.000000E+00
d(o16)/dt  =  0.000000E+00  d(ne20)/dt =  2.791414E-08    d(mg24)/dt =  0.000000E+00
1 - sum    = -6.617445E-24
eps_nuc    =  6.217517E+09     erg/g/sec

give the temperature, density, and mass fractions (h1, he4, c12, n14, o16, ne20, mg24) =>
hit return for T = 1e9 K, Rho = 1e4 g/cc, x(c12) = 1 ; enter -1 to stop

-1
STOP normal termination

For homework, edit sample_net.f90 and change the network and associated write statements.