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

[Ebrahim Hassani]

Hi dear Francis,

Thank you very much for your attention and also for your answers.

After reviewing the code several times, I could find the problem with my
code. In fact, I had changed the value of the log_L_lower_limit variable in
the inlist_start file from 1 to -4. After returning the value of
log_L_lower_limit to 1, the code worked correctly and I  could evolve the
1_M_Sun star until the white dwarf phase. Honestly speaking, I don't know
what the value of log_L_lower_limit determines in the inlist_start file
(but in the inlist_to_wd file, the value of log_L_lower_limit determines
the stopping condition for the star).

After correcting the above-mentioned mistake, I could run the code for
stars with 1.0-2.0 solar masses successfully (and until the white dwarf
phase). But when I increased the mass of the star to 2.5 solar mass (or
higher masses e.g. 3.0 M_Sun), I encountered a new problem. The attached
file is the screenshot of the final error message that I had got for the
2.5 solar-mass star. The code produced the same problem for other higher
mass stars (e.g. 3.0 M_Sun) too. This time stars are evolving until the AGB
phase, but they don't evolve further, and then they don't reach the white
dwarf phase.

May I ask again what might be the reason for the new error message? It is
worth stressing that, this problem happens just for high-mass stars
(2.5-3.0 solar masses) and not for low-mass ones (1.0-2.0 solar masses). My
guess is, this problem happens because of the new source of energy that we
defined in the src/run_star_extras.f90 file and through dark matter
annihilation, but I am not sure about this.

I would really appreciate any of your feedback and any comments


All the best
Ebrahim



On Mon, Sep 6, 2021 at 5:34 AM Francis Timmes <fxt44 at mac.com> wrote:

> 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!
>
> fxt
>
>
>
>
>
>
> > 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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