[Mesa-users] New public release r11701 (recommended upgrade)

[Warrick Ball]

Hi,

> We thank those (Conny Aerts, Joey Mombarg, Warrick Ball) who provided problem reports.

I just wanted to defer my thanks to Andrea Miglio and his team who brought 
the issue to me in the first place.

W


------------
Warrick Ball
Postdoc, School of Physics and Astronomy
University of Birmingham, Edgbaston, Birmingham B15 2TT
W.H.Ball at bham.ac.uk
+44 (0)121 414 4552


On Sat, 4 May 2019, mesa-users at lists.mesastar.org wrote:

> Hi All,
>
> I'm pleased to announce the release of MESA r11701.  The MESA developers
> strongly recommend that you upgrade to this version if you are using
> r11532 or r11554.
>
> This release corrects two equation of state related issues present in
> these versions (described in more detail below).  We thank those (Conny
> Aerts, Joey Mombarg, Warrick Ball) who provided problem reports.
>
> Other changes are minor. The install process has been visually
> streamlined.  Archive files are now compressed using xz (instead of
> bzip2) which results in a slightly smaller download size.
>
> When upgrading, we also suggest that users upgrade to the recently
> released 20190503 SDKs.
>
> The website will be updated shortly.
>
> Josiah
>
>
> Summary of EOS issues
>
> The EOS issues are related to DT2 and ELM (see MESA V, Appendix A).
> As of r11532, these EOS options were turned on by default, i.e.
>
>  use_eosDT2 = .true.  ! replaces eosDT
>  use_eosELM = .true.  ! replaces HELM
>
> These EOSes rely on the same underlying microphysical data as previous
> MESA versions, but interpolate differently.
>
>
> eosDT2 Issue: X Interpolation
>
> eosDT2 has been corrected to default to the same X (hydrogen mass
> fraction) interpolation scheme as eosDT.
>
> MESA r11532 and r11554 defaulted to linear interpolation in X.  This was
> a change in behavior from the old eosDT, which uses a higher order
> scheme.  One manifestation of this was mean molecular weight profiles
> that are piecewise-linear (i.e. continuous but not smooth).  This can
> become particularly apparent in the Brunt.
>
>
> eosELM Issue: Composition coverage
>
> eosELM has been corrected to better match HELM and to automatically fall
> back to HELM outside its range of applicability.
>
> ELM (which is a tabulated version of HELM) could return significantly
> different answers than HELM at the same conditions.  Because the ELM
> tables are only compiled at particular values of (abar, zbar), MESA
> interpolates.  The details of this interpolation, plus some issues with
> table placement, meant that there were places where the values returned
> by ELM were more than 1% different than the HELM value.
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>