[mesa-users] issue with OP AGSS09

[Aaron Dotter]

Hi Radek,

 - at the moment using OP A09 for any problem dealing with large log T is
> simply wrong?
>

Well, for logT > 8 it is wrong.


> - can we simply fix this and tell kap module to make blending at lower
> logT? (does the source of opacities at large  logT extend also down to
> logT=8 and is reliable there?)
>

Currently the blend with compton opacities is hard-wired in the code
between log T = 8.2 and 8.7.  However, the control over how to blend
between the Type1 and Type2 tables is in the user's control --  see the kap
controls section of star_job.defaults for more information.

[In case all the Type1/Type2 nonsense is confusing to anyone reading this,
the OPAL naming convention is tables for which the relative metal fractions
stay fixed is Type1 and those for which the C and O fractions are taken
separately from "Z" are Type2.]

I would recommend that you (a) use the Type2 tables and (b) put the
transition between Type1 and Type2 at logT=8.  That should take care of the
missing data in the OP tables AND the problem of properly accounting for
the results of He-burning, which ought to be done anyway.

- does anyone know why the OP web application now produces the results only
> to logT=8, while for OP GS98 it was possible to go logT=8.7 (how OP gs98
> file was prepared: with web application or OPCD software?)
>

As far as I am aware, the OPCD software always officially supported up to
logT = 8 for as long as I've been following it.  The OP GS98 file
distributed with MESA is one that was directly available on their webpage,
current link is broken.  The more recent tables the format has changed
somewhat and is sloppier now than it used to be.  I don't know how that
GS98.OP17 file was generated, but I suspect it was made by someone within
the OP collaboration.

Aaron
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20131012/498ecddb/attachment.html>