[Mesa-users] 2.0 M_sun star did not reach the AGB phase

Francis Timmes fxt44 at mac.com
Mon Sep 6 01:04:11 UTC 2021

hi ebrahim,

your other_mesh_delta_coeff_factor routine is sufficiently complicated
that you may need to do additional debugging. in addition, there is an 
apparent reliance on the default timestep controls; tightening those
should be considered. 

if the model works to your satisfaction for a mass of 1.0, then i suggest 
making some plots of what the model is doing and also noting what 
physical variable (central temperature, central density, etc) controls the timesteps. 
then try a model with a smaller mass change, say, 1.1 msun. what changes and why? 
repeat this analysis for a mass of 1.2 and so on. perhaps by the time you get 
to 1.5 msun or so it will be clearer why your model is stalling. also, note that
helium ignition is rather different for 1.0 msun that it is for 2 msun ...

happy hunting!


> On Aug 29, 2021, at 9:46 PM, Ebrahim Hassani via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> Dear mesa-users
> I used 1M_pre_ms_to_wd star in mesa-r15140/star/test_suite to consider dark matter effects in stars. I could edit and run the code successfully. But when I changed the mass of the star from 1.0 M_sun to 2.0 M_sun the code again worked without any problem. But for the 2.0 M_sun star, the star did not finish the run. It took about 10^5 steps until now and it did not reach the AGB phase or later phases. In addition, until 10^5 step, the mass of the star did not reduce due to e.g. stellar winds, etc.
> The code of the 2.0 M_sun star is available at (see the attached files too):
> https://drive.google.com/file/d/1FpFxApMOeZ6tK2Pzr3XbkAk1ZKqhsQhm/view?usp=sharing
> I used this code (in jupyter notebook) to plot the H-R diagram (see the attached files too):
> https://drive.google.com/file/d/1iDOTf6L1sJXUkeO3cupHQOas-RIaRnwc/view?usp=sharing
> It is worth mentioning that I mostly edited the run_star_extras.f90 file in the src folder to consider dark matter effects. I also uncommented "max_model_number = ..." command in inlist files. I also changed the amount of "log_L_lower_limit" values in inlist files.
> May I ask what might be the possible problem of the code that it did not reach to AGB phases? And how can I solve this problem?
> I would greatly appreciate any of your comments.
> Best regards,
> Ebrahim Hassani
> <Cap_Rate.ipynb><2M_pre_ms_to_wd_Mwimp_1D2_Rho_0.zip>_______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users

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