# kap module controls¶

The MESA/kap parameters are given default values here. The actual values as modified by your inlist are stored in the Kap_General_Info data structure. They can be accessed by code at runtime using the kap_handle to get a pointer to it.

## Base metallicity¶

### Zbase¶

The base metallicity for the opacity tables. This provides the reference metallicity necessary to calculate element variations. Physically, this usually corresponds to the initial metallicity of the star.

```
Zbase = -1
```

## Table selection¶

### kap_file_prefix¶

Select the set of opacity tables for higher temperature, hydrogen-rich conditions. Also referred to as Type1 tables. See Blend controls to understand precisely when these tables are used.

These tables use the value of `Zbase`

for Z, unless `use_Zbase_for_Type1 = .false.`

.

The Type1 tables cover a wider range of X and have a higher resolution in Z for each X than Type2. The Type1 tables are for (X,Z) pairs from the following sets:

- X: 0.0, 0.1, 0.2, 0.35, 0.5, 0.7, 0.8, 0.9, 0.95, 1-Z
- Z: 0.0, 1e-4, 3e-4, 1e-3, 2e-3, 4e-3, 1e-2, 2e-2, 3e-2, 4e-2, 6e-2, 8e-1, 1e-1

Available options:

`'gn93'`

`'gs98'`

`'a09'`

`'OP_gs98'`

`'OP_a09_nans_removed_by_hand'`

```
kap_file_prefix = 'gs98'
```

### kap_CO_prefix¶

Select the set of opacity tables for higher temperature, hydrogen-poor/metal-rich conditions.
Also referred to as Type2 tables.
Critically, Type2 tables account for C and O enhancement during and after He burning.
See Blend controls to understand precisely when these tables are used.
abundances previous to any CO enhancement.
Ignored if `use_Type2_opacities = .false.`

.

These tables use the value of `Zbase`

as the base metallicity.

The Type2 tables are for (X,Z) pairs from the following sets:

- X: 0.0, 0.03, 0.10, 0.35, 0.70
- Z: 0.00, 0.001, 0.004, 0.01, 0.02, 0.03, 0.05, 0.1

Available options:

`'gn93_co'`

`'gs98_co'`

`'a09_co'`

```
kap_CO_prefix = 'gs98_co'
```

### kap_lowT_prefix¶

Select a set of opacity tables for lower temperatures.

Available options:

`'lowT_Freedman11'`

`'lowT_fa05_gs98'`

`'lowT_fa05_gn93'`

`'lowT_fa05_a09p'`

`'lowT_af94_gn93'`

`'lowT_rt14_ag89'`

`'kapCN'`

`'AESOPUS'`

`kap_CN`

uses tables from

Lederer, M. T.; Aringer, B. (2009)Low temperature Rosseland opacities with varied abundances of carbon and nitrogen

`'AESOPUS'`

uses tables from AESOPUS

Marigo, P.; Aringer, B. (2009)Low-temperature gas opacity. ÆSOPUS: a versatile and quick computational tool

Specify which file using `AESOPUS_filename`

.
The file is first looked for in the work directory. If not found, then data/kap_data is searched.
Currently one set of opacities is provided, with the filename `'AESOPUS_AGSS09.h5'`

.

To see more detail about the composition details of the tables set `show_info = .true.`

.

You can generate your own tables with their web interface at http://stev.oapd.inaf.it/cgi-bin/aesopus . See kap/preprocessor/AESOPUS/README for information on preparing the tables for MESA.

```
kap_lowT_prefix = 'lowT_fa05_gs98'
AESOPUS_filename = '' ! used only if kap_lowT_prefix = 'AESOPUS'
```

## Blend controls¶

### use_Zbase_for_Type1¶

If true, then if `use_Type2_opacities = .true.`

, Type1 opacities will be computed
using `Zbase`

instead of `Z`

when Z > Zbase. This helps with blending from Type1 to Type2.
Ignored if `use_Type2_opacities = .false.`

.

```
use_Zbase_for_Type1 = .true.
```

### use_Type2_opacities¶

Select whether to use Type2 opacity tables (see kap_CO_prefix).
Even when true, in regions where hydrogen is
above a given threshold, or the metallicity is not significantly higher than
`Zbase`

, Type1 tables are used instead, with blending regions to smoothly
transition from one to the other (see following controls).

```
use_Type2_opacities = .true.
```

### kap_Type2_full_off_X¶

### kap_Type2_full_on_X¶

Switch to Type1 if X too large.
Type2 is full off for `X >= kap_Type2_full_off_X`

Type2 can be full on for `X <= kap_Type2_full_on_X`

.

```
kap_Type2_full_off_X = 1d-3
kap_Type2_full_on_X = 1d-6
```

### kap_Type2_full_off_dZ¶

### kap_Type2_full_on_dZ¶

Switch to Type1 if dZ too small `(dZ = Z - Zbase)`

.
Type2 is full off for `dZ <= kap_Type2_full_off_dZ`

.
Type2 can be full on for `dZ >= kap_Type2_full_on_dZ`

.

```
kap_Type2_full_off_dZ = 0.001d0
kap_Type2_full_on_dZ = 0.01d0
```

X and dZ terms are multiplied to get actual fraction of Type2.
The fraction of Type2 is calculated for each cell depending on the X and dZ for that cell.
So you can be using Type1 in cells where X is large or dZ is small,
while at the same time you can be using Type2 where X is small and dZ is large.
When `frac_Type2`

is > 0 and < 1, then both Type1 and Type2 are evaluated and
combined linearly as `(1-frac_Type2)*kap_type1 + frac_Type2*kap_type2`

.
Add `kap_frac_Type2`

to your profile columns list to see `frac_Type2`

for each cell.

### kap_blend_logT_upper_bdy¶

### kap_blend_logT_lower_bdy¶

Region to blend between higher temperature tables (see kap_file_prefix and kap_CO_prefix) and lower temperature tables (see kap_lowT_prefix).

The upper/lower blend boundary will be clipped to the true extent
of the opacity tables. The upper boundary will be min of
`kap_blend_logT_upper_bdy`

and the max logT for lowT tables.
The lower boundary will be max of `kap_blend_logT_lower_bdy`

and min logT for highT tables. The typical min logT of the
higher temperature tables tables is 3.75. Check your tables to
be sure.

It is probably a good idea to keep the blend away from H ionization. logT upper of about 3.9 or a bit less will do that.

```
kap_blend_logT_upper_bdy = 3.88d0
kap_blend_logT_lower_bdy = 3.80d0
```

## Interpolation options¶

### cubic_interpolation_in_X¶

type of interpolation in X. true is cubic; false is linear.

```
cubic_interpolation_in_X = .false.
```

### cubic_interpolation_in_Z¶

type of interpolation in Z. true is cubic; false is linear.

```
cubic_interpolation_in_Z = .false.
```

## Custom tables¶

If the prefix options in Table selection above do not match one of the available options,
MESA still searches for files in `data/kap_data`

with the given prefix.
This allows for custom tables. However, the user must also indicate
the X and Z values for which the tables are provided.

Separate controls exist for each class of prefix.

### user_kap_Xs¶

X values for the tables (length `user_num_kap_Xs`

).
Values such that X + Z > 1 will have X reduced to 1-Z.
Choose `user_num_kap_Xs_for_this_Z`

such that at most 1 X value for each Z will be reduced in this way.

```
! user_kap_Xs = 0.0d0, 0.1d0, 0.2d0, 0.35d0, 0.5d0, 0.7d0, 0.8d0, 0.9d0, 0.95d0, 1.0d0
```

### user_kap_Zs¶

Z values for the tables (length `user_num_kap_Zs`

).

```
! user_kap_Zs = 0.000d0, 0.0001d0, 0.0003d0, 0.001d0, 0.002d0, 0.004d0, 0.01d0, 0.02d0, 0.03d0, 0.04d0, 0.06d0, 0.08d0, 0.100d0
```

### user_num_kap_Xs_for_this_Z¶

At different values of Z, the number of values of X may change. In particular, tables with `X > 1-Z`

will not exist.
Use the first N (`<= user_num_kap_Xs`

) X values for the tables of the corresponding Z (length `user_num_kap_Zs`

).

```
! user_num_kap_Xs_for_this_Z = 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 9, 9, 8
```

### user_kap_CO_Xs¶

X values for the tables (length `user_num_kap_CO_Xs`

).

```
! user_kap_CO_Xs = 0.00d0, 0.03d0, 0.10d0, 0.35d0, 0.70d0
```

### user_kap_CO_Zs¶

Z values for the tables (length `user_num_kap_CO_Zs`

).

```
! user_kap_CO_Zs = 0.000d0, 0.001d0, 0.004d0, 0.010d0, 0.020d0, 0.030d0, 0.050d0, 0.100d0
```

### user_num_kap_CO_Xs_for_this_Z¶

At different values of Z, the number of values of X may change. In particular, tables with `X > 1-Z`

will not exist.
Use the first N (`<= user_num_kap_CO_Xs`

) X values for the tables of the corresponding Z (length `user_num_kap_CO_Zs`

).

```
! user_num_kap_CO_Xs_for_this_Z = 5, 5, 5, 5, 5, 5, 5, 5
```

### user_kap_lowT_Xs¶

X values for the tables (length `user_num_kap_lowT_Xs`

).
Values such that X + Z > 1 will have X reduced to 1-Z.
Choose `user_num_kap_lowT_Xs_for_this_Z`

such that at most 1 X value for each Z will be reduced in this way.

```
! user_kap_lowT_Xs = 0.0d0, 0.1d0, 0.2d0, 0.35d0, 0.5d0, 0.7d0, 0.8d0, 0.9d0, 0.95d0, 1.0d0
```

### user_kap_lowT_Zs¶

Z values for the tables (length `user_num_kap_lowT_Zs`

).

```
! user_kap_lowT_Zs = 0.000d0, 0.0001d0, 0.0003d0, 0.001d0, 0.002d0, 0.004d0, 0.01d0, 0.02d0, 0.03d0, 0.04d0, 0.06d0, 0.08d0, 0.100d0
```

### user_num_kap_lowT_Xs_for_this_Z¶

At different values of Z, the number of values of X may change. In particular, tables with `X > 1-Z`

will not exist.
Use the first N (`<= user_num_kap_lowT_Xs`

) X values for the tables of the corresponding Z (length `user_num_kap_lowT_Zs`

).

```
! user_num_kap_lowT_Xs_for_this_Z = 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 9, 9, 8
```

## Conductive opacity options¶

### include_electron_conduction¶

add conduction opacities to radiative opacities

```
include_electron_conduction = .true.
```

### use_blouin_conductive_opacities¶

Use fits from Blouin et al. (2020) for H and He in the regime of moderate coupling and moderate degeneracy.

```
use_blouin_conductive_opacities = .true.
```

## Miscellaneous controls¶

### show_info¶

if true, then output additional information as the opacities are loaded. this is particularly useful to see the detailed composition coverage of the AESOPUS opacity files.

```
show_info = .false.
```

## Other hooks¶

Control whether to use other hooks. See `kap/other`

.

### use_other_elect_cond_opacity¶

Replace electron conduction opacity routine

```
use_other_elect_cond_opacity = .false.
```

### use_other_radiative_opacity¶

Replace radiative opacity routine. The standard routine evaluates the opacity using the low-T and high-T tables.

```
use_other_radiative_opacity = .false.
```

## Debugging controls¶

Specify a range of calls for which to receive debugging information.

```
dbg = .false.
logT_lo = -1d99
logT_hi = 1d99
logRho_lo = -1d99
logRho_hi = 1d99
X_lo = -1d99
X_hi = 1d99
Z_lo = -1d99
Z_hi = 1d99
```