[Mesa-users] Test not getting past the AGB stage

[Kimberly Appel]

Hi Pablo,

Thank you for your reply. I apologise if I am asking basic questions but I
am new to MESA and I am trying to understand how MESA works.

What parameter can I use to set and adjust increase the mass-loss rate? The
mass is not decreasing at all as you said and I am trying to get it to a
lower luminosity so that it can reach the WD stage and the test to reach
the WD linlist. Should I be using a different wind scheme for this
particular mass star? The number of options available on the MESA
documentation is a bit overwhelming and I really don't know what to choose
for this problem. I feel like the 1Msun wind schemes are more appropriate
for this model.

Your help will be greatly appreciated.

Kind regards,
Kim.

On Wed, Jun 17, 2020 at 9:17 AM Pablo Marchant <pamarca at gmail.com> wrote:

> Hi Kimberly,
>
> from your pgplot snapshot included with your files I can see that your
> model is evolving during these timesteps. The helium core mass is slowly
> increasing, and there are traces of thermal pulses in your Kippenhahn
> diagram.This phase can be expensive to model, with weaker mass loss rate
> prescriptions leading to more pulses and a longer runtime. Now, in
> particular, you should notice that the mass of your model remains at
> exactly 3 Msun and the mass loss rate is zero. This means your helium core
> mass will just keep growing and you will not get a WD out of this.
>
> I'm guessing this is a consequence of the multi-inlist nature of your
> setup. If you see the rn script you'll notice that first the simulation is
> run using inlist_start and then continues with inlist_to_end_agb, which
> includes winds. If you see inlist_start, you'll find this is the
> terminating condition
>
>        ! stop when the luminosity has decreased to 10 Lsun
>        ! for a 1 Msun star, this is roughly the on birthline
>        log_L_lower_limit = 1.2
>
> My guess is that you're not hitting that value, so you never move to the
> following inlist.
>
> Cheers
>
> On Wed, Jun 17, 2020 at 8:15 AM Kimberly Appel via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
>> Dear all,
>>
>> The version of MESA I am using is r12778, the version of MESA SDK I am
>> using is 20.3.2 (64-Linux) and my operating system is Linux.
>>
>> So, I am trying to run a 4Msun model from the pre-main sequence to the
>> pre-white dwarf stages. The model does get past the pre-main sequence, the
>> main sequence, and the helium flash stages. However, it does not get past
>> the AGB stage, i.e, the log of the luminosity does not reach 1. The model
>> is like 'stuck' at that stage.
>>
>> To try to solve the problem, I adjusted the following parameters in the
>> inlist_start and inlist_to_wd files:
>>
>> (i)    Increased initial_z from 0.0001 to 0.002;
>> (ii)   increased the number of tries from 15 to 80;
>> (iii ) increased the maximum model number from 6000 to 15 000;
>> (iv)  increased the envelope mass limit from 1d-9 to 3d-9
>> (v)  increased the log lower limit of the luminosity from -1 to 1
>>
>> But none of those adjustments helped at all. The mass of the star does
>> not even decrease as the test runs (remains constant).
>>
>> I am really worried because the test runs ~6 hours but no changes are
>> observed after the test terminates (remains on the AGB stage). When the run
>> terminates, I get this output
>>
>>  png/grid1011994.png/png
>>                                  WARNING: rel_run_E_err       11995
>>  1.7866252135531238D-01
>>                                  WARNING: rel_run_E_err       11996
>>  1.7865795134998794D-01
>>                                  WARNING: rel_run_E_err       11997
>>  1.7865344035982969D-01
>>  png/grid1011997.png/png
>>                                  WARNING: rel_run_E_err       11998
>>  1.7864896005027328D-01
>>                                  WARNING: rel_run_E_err       11999
>>  1.7864450912957677D-01
>>
>> stop because model_number >= max_model_number
>>     15000    15000
>>
>> It's like MESA is not reading the other inlist files.
>>
>> Is there anything, in particular, I am missing?
>>
>> I've attached the inlist files and models. Your help will be greatly
>> appreciated.
>>
>> Kind regards,
>> Kim.
>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>
>>
>
> --
> Pablo Marchant Campos
> M.Sc on Astrophysics, Universidad Católica de Chile
> PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
>
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