[Mesa-users] New MESA release 24.08.1

Wed Aug 21 12:03:40 UTC 2024

Hello everyone,

We are pleased to announce a the official public release of MESA, r24.08.1
<https://docs.mesastar.org/en/24.08.1/>, which can be downloaded from
Zenodo: https://zenodo.org/doi/10.5281/zenodo.2602941
<https://zenodo.org/records/11502397>

For a complete list of important changes since the last release, see the
changelog <https://docs.mesastar.org/en/24.08.1/changelog.html>. Here is a
brief summary:

A new set of MESA SDKs (24.7.1) are also available for download
<http://user.astro.wisc.edu/~townsend/static.php?ref=mesasdk>.

(Python 3.5+ is now required for MESA installation)

New Features:

High Temperature Opacity Tables

Type 1 Rosseland-mean opacity tables from The Los Alamos OPLIB database (Colgan
et al. 2016 <https://ui.adsabs.harvard.edu/abs/2016ApJ...817..116C/abstract>)
are now available (Farag et al. 2024
<https://doi.org/10.3847/1538-4357/ad4355>). These tables cover the region
0.0 ≤ X ≤ 1 − Z and 0.0 ≤ Z ≤ 0.2. Each set of OPLIB opacity tables
contains 1194 individual tables, a dramatic increase in table density (in
the X–Z plane) over the standard 126 individual tables provided in previous
opacity releases. These tables are available for four solar-scaled
abundance mixtures constructed from photospheric estimates of the solar
heavy element abundance: (GS98, Grevesse & Sauval 1998
<https://ui.adsabs.harvard.edu/abs/1998SSRv...85..161G/abstract>),
(AGSS09(a09p),
Asplund et al. 2009
<https://ui.adsabs.harvard.edu/abs/2009ARA%26A..47..481A/abstract>), (AAG21,
Asplund et al. 2021
<https://ui.adsabs.harvard.edu/abs/2021A%26A...653A.141A/abstract>), and (MB22,
Magg et al. 2022 <https://doi.org/10.1051/0004-6361/202142971>). Users can
adopt this new set of tables by selecting one of the following options for
kap_file_prefix:

   -

   'oplib_gs98'
   -

   'oplib_agss09'
   -

   'oplib_aag21'
   -

   'oplib_mb22'

See Overview of kap module
<https://docs.mesastar.org/en/release-r24.06.1-rc1/kap/overview.html#overview-of-kap-module>
and kap_file_prefix
<https://docs.mesastar.org/en/release-r24.06.1-rc1/kap/defaults.html#kap-file-prefix>
for more details on the implementation of these tables. For further details
on these new OPLIB opacity tables, a direct comparison with the Type 1
OPAL/OP tables as well as their effect on solar models can be found in Farag
et al. 2024 <https://doi.org/10.3847/1538-4357/ad4355>.

Low Temperature Opacity Tables

Low temperature Rosseland-mean opacity tables for both (AAG21, Asplund et
al. 2021 <https://ui.adsabs.harvard.edu/abs/2021A%26A...653A.141A/abstract>),
and (MB22, Magg et al. 2022 <https://doi.org/10.1051/0004-6361/202142971>)
solar-scaled abundance mixtures have been privately communicated by Jason
Ferguson. These opacity tables were computed following the approach of Ferguson
et al. (2005)
<https://ui.adsabs.harvard.edu/abs/2005ApJ...623..585F/abstract>. Users can
adopt this new set of tables by selecting one of the following options for
kap_lowT_prefix
<https://docs.mesastar.org/en/release-r24.06.1-rc1/kap/defaults.html#kap-lowt-prefix>
:

   -

   'lowT_fa05_mb22'
   -

   'lowT_fa05_aag21'

Opacity interpolation

We have updated the opacity interpolation scheme to provide much higher
quality derivatives when doing cubic interpolation in composition. MESA
interpolates across opacity tables in the X–Z plane through the use of two
consecutive 1D splines. MESA offers users the ability to choose linear or
cubic interpolation for these splines, while leaving the default as linear
interpolation.

‘cubic_interpolation_in_X = .false.’

‘cubic_interpolation_in_Z = .false.’

This choice of default was primarily due to the fact that the previous
cubic composition interpolation scheme in MESA suffered from poor quality
interpolated opacity derivatives with respect to density and temperature,
which often disagreed with the numerical derivatives produced via nearest
neighbor Richardson extrapolation.

Chem
New initial metal mass fractions initial_zfracs taken from photospheric
estimates of the solar heavy element abundances in (AAG21, Asplund et al.
2021) and (MB22, Magg et al. 2022) are now available. See initial_zfracs
<https://docs.mesastar.org/en/release-r24.06.1-rc1/reference/star_job.html#initial-zfracs>
for more details.

Update to Starspots

star spot parameters ``fspot`` and ``xspot`` have been added as general
controls and are now accessible outside of ``test_suite/starspots/``. Star
spots are off by default.

Replacement of HDF5io for ForUM

The HDF5io module (in the :file:`hdf5io` subdirectory) has been

replaced by the ForUM module (in the :file:`forum`

subdirectory). HDF5io provided a high-level wrapper around the HDF5
<https://www.hdfgroup.org/solutions/hdf5/>

input/output library <https://www.hdfgroup.org/solutions/hdf5/>; it was
based on source files copied from an alpha version of

ForUM. ForUM <https://github.com/rhdtownsend/forum> (short for Fortran
Utility

Modules) is a small library providing input/output, operating system,

memory management and utility routines for Fortran.

Now that ForUM has officially been released, and also that recent GYRE

releases also require ForUM, it made sense to include the official

distribution of ForUM within MESA. One important consequence of this

decision is that ForUM uses fypp <https://github.com/aradi/fypp> for
pre-processing and templating, and fypp in turn requires a Python
interpreter.

As a consequence, building MESA now requires Python (3.5 or newer) be
installed.

Update to GYRE 7.2.1

The GYRE distribution bundled with MESA has been updated to release

7.2.1. Full details about this release can be found on the GYRE
<https://gyre.readthedocs.io/en/v7.2.1/>

documentation page <https://gyre.readthedocs.io/en/v7.2.1/>. From the
perspective of MESA users, the significant change arising from this update
is that the MESA-to-GYRE interface is now provided via the library file
:file:`libgyre_mesa.a` and the module file

:file:`gyre_mesa_m.mod` (previously, these were :file:`libgyre.a` and

:file:`gyre_lib.mod`, respectively). A new variable, `LOAD_GYRE`, has

been added to :file:`utils/makefile_header` to simplify linking

against :file:`libgyre_mea.a`. These changes will likely only affect

those users that make calls to GYRE from inside

:file:`run_star_extras.f90`.

Bug Fixes:

   1.

   There has been a bug present in the rates module due to the incorrect
   phase space factors for reverse reaction rates involving greater than 2
   reactants or products. This bug resulted in inconsistent equilibrium
   compositions when the network evolves into nuclear statistical equilibrium
   (NSE), at temperatures exceeding 4 GK. This bug effects users who evolve
   models into NSE using large reaction networks. This includes evolving
   massive stars to core-collapse. Smaller networks such as the ‘approx21’
   networks are less affected. We strongly recommend that users update to the
   latest MESA release. See gh-575
   <https://github.com/MESAHub/mesa/issues/575>
   2.

   MESA no longer produces a segmentation fault if it tries to increase the
   number of cells beyond max_allowed_nz.
   3.

   A bug in the pgbinary axes definitions resulted in models crashing when
   running in single star mode and has been corrected. Another bug inhibited
   the mass of the not modeled star from being displayed in the pgbinary panel
   and has also been corrected. See gh-634
   <https://github.com/MESAHub/mesa/issues/634>

We are happy to announce two new members have joined the MESA developers
team: Mathieu Renzo and Jared Goldberg. As always, the full list of current
MESA developers can be found here:

    https://docs.mesastar.org/en/latest/about.html#developers
<https://urldefense.com/v3/__https://docs.mesastar.org/en/latest/about.html*developers__;Iw!!IKRxdwAv5BmarQ!YAF9Kn0Z0cXMxx2CGoGpA4_iGv1sY4EoWqX4LvEhye_CnUPZxqbl6BOqzudod5diqxzRZIqB9gbEFeeotn17ng8lr-EprQ$>

With thanks to the following members of the community for contributions:
Ryosuke Hirai, Aldana Grichener, Vincent Vanlaer

We welcome contributions from the community. If you want to contribute to
MESA, we have a guide: https://docs.mesastar.org/en/latest/contributing.html
<https://urldefense.com/v3/__https://docs.mesastar.org/en/latest/contributing.html__;!!IKRxdwAv5BmarQ!dFfyYL414f_nuyOgsnLUOCwR73pHNQ0WutdCYaJKVaWvAyNBAlVyNV98jydPqr2KuL2IuK6aDwXNeiNT6AE3hWlV$>

Contributions can take many forms, including bug reports, documentation
fixes, and new code or science. Not everyone has to be a coder to
contribute. If you have something you want to contribute but have doubts
about it, then feel free to reach out to any of the MESA developers and we
can provide help and guidance.

Cheers,
Ebraheem, on behalf of the MESA developers
<https://urldefense.com/v3/__https://docs.mesastar.org/en/latest/about.html*developers__;Iw!!IKRxdwAv5BmarQ!dFfyYL414f_nuyOgsnLUOCwR73pHNQ0WutdCYaJKVaWvAyNBAlVyNV98jydPqr2KuL2IuK6aDwXNeiNT6CLxTRCt$>:
Warrick Ball, Evan Bauer, Earl Bellinger, Lars Bildsten, Matteo Cantiello,
Matthias Fabry, Ebraheem Farag, Eoin Farrell, Meridith Joyce, Pablo
Marchant, Philip Mocz, Joey Mombarg, Radek Smolec, Anne Thoul, Frank
Timmes, Rich Townsend, Bill Wolf, Jared Goldberg, & Mathieu Renzo
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