[Mesa-users] Differences between MESA r10398 and 25.12.1 for rotating very massive stars

[Natalija M]

Hello Ebraheem,

Thank you for the quick reply.

I did try different values of the overshooting parameter. From the tests so
far, it seems that f = 0.345 reproduces the solar metallicity case better
compared to the old models. However, in general the difference between f =
0.345 and f = 0.25 remains relatively small through most of the evolution
and only becomes more noticeable toward the very end of the evolution for
the new version. Because of this, I am not sure that the overshooting alone
explains why the models from the older version evolve toward higher
effective temperatures in the HR diagram almost immediately.

I’ve attached HR diagrams for both the solar and SMC metallicity cases with
the different overshooting values.


Best regards,

Natalija



On Mon, Mar 16, 2026 at 7:22 PM Farag, Ebraheem <ebraheem.farag at yale.edu>
wrote:

> Hello Natalija,
>
> I notice you are using different amounts of overshoot in each inlist,
> perhaps that explains some of the differences you are seeing?
>
> -EbF
> ------------------------------
> *From:* Mesa-users <mesa-users-bounces at lists.mesastar.org> on behalf of
> Natalija M via Mesa-users <mesa-users at lists.mesastar.org>
> *Sent:* Monday, March 16, 2026 3:54 AM
> *To:* mesa-users at lists.mesastar.org <mesa-users at lists.mesastar.org>
> *Subject:* [Mesa-users] Differences between MESA r10398 and 25.12.1 for
> rotating very massive stars
>
>
> Dear MESA users,
>
> I am currently trying to switch from r10398 to 25.12.1, and while doing so
> I noticed some differences in the results.
>
> I evolved rotating very massive stars with low metallicity using the
> inlists attached below (which are quite similar for both versions). For
> solar metallicity, the results are in very good agreement between the two
> versions. However, for lower metallicities, the models evolve very
> differently, as illustrated in the HR diagram. I am not sure what in the
> older version leads to this behavior.
>
> I would greatly appreciate any help or guidance.
>
> Best regards,
> Natalija Mladenović
>
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