[Mesa-users] Primary star evolution stalled in binary simulation

[Wolf, William M]

Hi Alex,

That can be a tough one to solve. I’d recommend fiddling with different atmostphere controls to see if something is more stable. Sometimes this control can help: “convergence_ignore_equL_residuals = .true.” It doesn’t solve any problem; it just tells the solver to stop caring about residuals in the luminosity equation. I find this helps when I’ve got issues with the surface of my models. No guarantees, but those are what I would try in your situation.

Regards,

Bill

From: Mesa-users <mesa-users-bounces at lists.mesastar.org> on behalf of Alex Duran via Mesa-users <mesa-users at lists.mesastar.org>
Date: Thursday, August 28, 2025 at 2:26 PM
To: mesa-users at lists.mesastar.org <mesa-users at lists.mesastar.org>
Subject: [Mesa-users] Primary star evolution stalled in binary simulation
Hi all,

I'm trying to evolve a binary model grid to study mass transfer. While analyzing a particular system, I notice that, at some point in the mass transfer phase, the code solver has trouble developing the primary (donor) star; this can be seen in the HR diagram, as loops in Teff and luminosity (attached image). The retries look something like this:

 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry: get_T_tau -- L <= 0    2032
 retry    2032
 retry:  logT > hydro_mtx_max_allowed_logT          68    2032
 retry    2032
 retry:  adjust_correction failed in eval_equations -- give up in solver    2032
 retry    2032

After a long effort varying parameters in the inlists, I discovered that the problem is solved by disabling the do_jdot_ml parameter. However, this can be a problem for my analysis, since I am interested in studying how different sources of angular momentum loss affect mass transfer. Has anyone ever encountered this problem? And if so, how did they solve it? I am attaching the inlists (for stars and binary), and also the extras files (for both star and binary evolution). The files I attached correspond to M1=1 Msun, M2=0.5 Msun and Porb=3.839 days, but I am having the same problem for periods between ~2 and ~14 days, for the same combination of masses.

Thank you in advance,
Cheers
--
Alex Durán-Reyes
MSc in Astrophysics, Universidad de Valparaíso
PhD Student in Astrophysics, Universidad de Valparaíso
alex.duran at postgrado.uv.cl<mailto:alex.duran at postgrado.uv.cl>
alex.fabian.dr at gmail.com<mailto:alex.fabian.dr at gmail.com>
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