[Mesa-users] Numerical issues during Helium flash

[Ana Antonini]

Hi Theo,

Without extra information, I'd say you can try adding some extra mesh and
timestep controls to regions/quantities of interest, like "
delta_lgL_He_limit",  and see if it helps.
Changing to the energy_eqn_option to "eps_grav" might also be helpful.
Another thing that guides me when starting a new project with MESA is
finding out if there are any works on the subject that use MESA, and seeing
what kinds of controls and physics those works are adopting.

We could say more if you provide us with more information. For example,
what is MESA reporting as the reason for bringing down the timesteps?
Perhaps also a little of the terminal output when timesteps start to
decrease a lot.

Good luck on your mesa journey!
Best,
Ana Antonini


Em qui., 12 de fev. de 2026, 9:52 AM, Théo-Courty via Mesa-users <
mesa-users at lists.mesastar.org> escreveu:

> Dear Mesa users
>
>
> I’m a PhD student fairly new to Mesa. I’m currently trying to evolve stars
> with different initial masses from ZAMS to WDCS. When I try to evolve lower
> mass star (1-2 Msun), I come across numerical difficulties during He Flash
> phase: the timestep becomes very small (log dt < -8 yr) and the simulation
> then takes forever (> ~10-20h) or can even stop due to timestep limit. My
> inlists are based on the test suite *make_co_wd* and I’m using version
> r25.12.1. I’m looking for advices/workarounds to ease this phase so the
> simulations can run in a reasonable amount of time. I’m attaching my
> inlists to this message. Thanks a lot!
>
>
> Best,
>
>
> Théo
>
>
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
>
>
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