[Mesa-users] [EXT] Surface_li7

[Mathieu Renzo]

Hi Bruno,

First you'll need a nuclear reaction network that explicitly traces 
li7.  This requires editing your `star_job` portion of the inlist.
The available nets are listed at $MESA_DIR/data/net_data/nets (and here: 
https://docs.mesastar.org/en/latest/net/nets.html). You can also make 
your own if you need to.

For example, you could use `pp_extras.net`, which has li7, be7 and b8 
added to the basic network used by default (if you open `pp_extras.net` 
you can see it loads `basic.net` and `add_pp_extras` and in the file for 
the latter, these isotopes and a few reactions are explicitly coded. 
Check that the reactions creating/destroying li7 you are interested in 
are included, if not, check the other nuclear reaction networks). To do 
so, in star_job add:

```
change_net = .true.
change_initial_net = .true.
new_net_name = 'pp_extras.net'
show_net_species_info = .true. ! at beginning of run, output list of 
isotopes tracked
```

This will change the net whether you start from a photo or the beginning 
of the run (because of the last flag set to true, this is optional).
Now, your MESA runs are aware of li7.

To add it to the output, you want to copy 
`$MESA_DIR/star/defaults/history_columns.list` in your work directory 
and uncomment (remove the leading `!` which is Fortran for comment) or 
add a line:

```
  surface li7
```
or
```
log_surface li7
```

of if you want all the isotopes surface mass fraction:
```
add_surface_abundances
```
or
```
add_log_surface_abundances
```
If you also want to track the spatial distribution throughout the star 
at a fixed point in time, you want to copy 
`$MESA_DIR/star/defaults/profiles_column.list` locally and uncomment/add 
the relevant lines for abundances (see detailed instructions in the file 
itself), so the mass fraction at each mesh point will also be logged in 
the `profile*.data` when created.

Hope this helps!
Mathieu


On 7/13/25 09:18, Bruno Lustosa via Mesa-users wrote:
> *
>
> *External Email*
>
> *
> ------------------------------------------------------------------------
> Wanting to study the Lithium abundance in Giants and using MESA 
> version r24, I would like to know what I should put in |&controls| (or 
> elsewhere) so that the Lithium (li7) abundance is also obtained as an 
> output. Forgive me for such an elementary question.
> Do I just add 'log_surface_li7' to the history.columns file?
>
> Cheers
> Bruno
>
>
>
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
-- 
Mathieu Renzo <https://www.as.arizona.edu/~mrenzo/>
Assistant Professor
University of Arizona - Steward Observatory
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