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

Bill Paxton paxton at kitp.ucsb.edu
Wed Jun 17 10:28:12 EDT 2020 

One way to see things is to look!  ;-)   Let’s make some plots and look at them for hints about what’s going on.

Make history plots of the evolution on the AGB.   

start plots when exhaust core He.  end them when system stalls or dies.

use model number as xaxis.   include some other things that might be useful to see.

some possible additions to history_columns.list

   ! integrated power from hydrogen and helium burning
   
      power_h_burn ! total thermal power from PP and CNO, excluding neutrinos (in Lsun units)
      power_he_burn ! total thermal power from triple-alpha, excluding neutrinos (in Lsun units)
      log_LH ! log10 power_h_burn
      log_LHe ! log10 power_he_burn

   ! conditions near surface
   
      log_L ! log10 luminosity in Lsun units
      luminosity
      log_Teff ! log10 effective temperature
      effective_T
      log_R ! log10 radius in Rsun units
      log_g ! log10 gravity

   ! misc
   
      v_div_csound_surf ! velocity divided by sound speed at outermost grid point
      surface_accel_div_grav ! (v - v_old)/dt divided by GM/R^2 at outermost grid point
      num_retries ! total during the run
      model_number ! counting from the start of the run
      star_age ! elapsed simulated time in years since the start of the run
      star_mass ! in Msun units
      log_abs_mdot ! log10(abs(star_mdot)) (in msolar per year)
      log_dt ! log10 time_step
      log_max_residual
      log_residual_norm
      num_solver_iterations ! iterations at this step

It will be interesting to see what you get for these. 

Bill



> On Jun 17, 2020, at 6:27 AM, Kimberly Appel via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi Anne
> 
> Thank you for your reply.
> 
> So, I did increase the maximum model number from 15 000 to 50 000 but that did not help - the model is just stuck at the AGB stage with no sign of it leaving the stage, i.e., the log of the surface luminosity is not decreasing at all and hence, it never reaches the WD stage. I also adjusted the RGB and AGB wind schemes and the number of time steps but that also did not help.  I am running out of options (I can think of) and really don't what to do now. 
> 
> Your help will be greatly appreciated. Thank you in advance.
> 
> Kind regards,
> Kim.
> 
> 
> 
> 
> On Wed, Jun 17, 2020 at 9:36 AM Anne Thoul <anne.thoul at gmail.com <mailto:anne.thoul at gmail.com>> wrote:
> Dear Kimberly
> 
> It looks like the run terminates with stop because model_number >= max_model_number
> You might want to increase the value of max_model_number to let your run go further.
> 
> Cheers
> Anne
> 
>> Le 17 juin 2020 à 09:17, Pablo Marchant via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> a écrit :
>> 
>> 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 <mailto: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 <mailto:mesa-users at lists.mesastar.org>
>> https://lists.mesastar.org/mailman/listinfo/mesa-users <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
>> _______________________________________________
>> mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
>> https://lists.mesastar.org/mailman/listinfo/mesa-users <https://lists.mesastar.org/mailman/listinfo/mesa-users>
>> 
> 
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