[Mesa-users] Stellar rotation

[Matteo Cantiello]

Hi Viviana,

MESA treats rotation under the shellular approximation (composition,
temperature, angular momentum… all constant on isobars). This allows to
solve the problem of  rotation in 1D. Transport of angular momentum and
chemical species in the vertical direction is treated in a diffusive
approximation, with different physical processes included via related
diffusive coefficients. This is all described in Sec. 6 of Paxton et al.
2013 (https://ui.adsabs.harvard.edu/abs/2013ApJS..208....4P/abstract) and
references therein.

Best,

Matteo

--
Matteo Cantiello - https://www.stellarphysics.org/
Research Scientist,  CCA, Flatiron Institute
Visiting Associate Researcher, Princeton University

Sent via Superhuman <https://sprh.mn/?vip=matteo.cantiello@gmail.com>


On Tue, Sep 17, 2024 at 2:46 PM, Viviana Beatríz Bolzicco <
mesa-users at lists.mesastar.org> wrote:

> Thank you Jared. for your answer.
> I would like to know what approximation or theory do MESA use for
> rotation in a star with many radiative zones. Is there any module?
>
> Thank you
>
> Viviana
>
> On Tue, Sep 17, 2024, 14:58 Jared Goldberg <jgoldberg at flatironinstitute.
> org> wrote:
>
> MESA is able to handle many radiative and convective zones, as it locally
> checks whether the zone should be radiative or convective at every zone in
> the model.
>
> To do this, MESA calculates the Schwartzschild or Ledoux criterion (see
> documentation
> <https://docs.mesastar.org/en/latest/reference/controls.html#use-ledoux-criterion>
> for turning this on) for convective instability in each shell in the model.
> This is a local condition, so MESA may calculate many radiative and
> convective layers, and switches energy transport between them. Typically
> MESA implements convection via Mixing Length Theory (See e.g. review by Joyce
> & Tayar <https://ui.adsabs.harvard.edu/abs/2023Galax..11...75J/abstract>),
> with the added capability of doing time-dependent convection (described
> in MESA VI
> <https://ui.adsabs.harvard.edu/abs/2023ApJS..265...15J/abstract>).
>
> For an example of a star with many layers (convective cores and shells and
> radiative zones too and a convective envelope), see e.g. the
> $MESA_DIR/star/test_suite/12M_pre_ms_to_core_collapse/ case in the
> test_suite, which takes a star to core-collapse which develops many layers
> of radiation and convection in between.
>
> The rest will depend on the science case you have in mind -- what kind of
> star do you have in mind? What are you trying to learn about it?
>
> ~Jared
>
> On Tue, Sep 17, 2024 at 12:52 PM Viviana Beatríz Bolzicco via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
> Dear all
>
> I'm just beginning to use MESA and I'm reading Bill Paxton et al (2013)'s
> Modules for experiments in stellar astrophysics (MESA): Planets,
> Oscillations, Rotation, and Massive stars.
> I'm interested to know how you resolve the problem of a star with more
> than one radiative zone.
>
> Regards
>
>  Viviana B. Bolzicco
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