[mesa-users] ionization fraction or kap table ?

[Jing Luan]

Thank you very much, Matthew :-D :-D

Sincerely,
Jing

On Thu, Jun 29, 2017 at 8:04 AM, Matthew Clayton <
matthew.clayton at exeter.ox.ac.uk> wrote:

> Hi Jing,
>
> That's right. You'll need 'use ionization_lib', and probably also 'use
> ionization_def' in order to tell the routine which species you're
> interested in. Take a look in $MESA_DIR/ionization/public/ for the details
> of how that works. You can also look at $MESA_DIR/star/private/profile_getval.f90
> for an example of eval_ionization being used.
>
> Cheers,
>
> Matthew
> ------------------------------
> *From:* Jing Luan [jingluan.xw at gmail.com]
> *Sent:* 29 June 2017 15:32
> *To:* Matthew Clayton
> *Cc:* mesa-users at lists.sourceforge.net
>
> *Subject:* Re: [mesa-users] ionization fraction or kap table ?
>
> Hi Matthew,
>
> Thank  you very much! If I want to call eval_ionization() in
> run_star_extras.f, do I just need to add a line saying 'use ionization_lib'
> near the beginning of that file please?
>
> Thank  you :-)
>
> Sincerely,
> Jing
>
> On Wed, Jun 28, 2017 at 4:32 AM, Matthew Clayton <
> matthew.clayton at exeter.ox.ac.uk> wrote:
>
>> Hi all,
>>
>> To add to Rich's answer, you can get MESA to output
>> neutral_fraction_H
>> neutral_fraction_He
>> and
>> avg_charge_He
>> to profiles. Different linear combinations of these 3 values will give
>> you all of the ionization fractions of H and He (exercise for reader).
>>
>> If you're looking to do calculations using ionization fractions within
>> MESA itself, you can use the ionization module. Call eval_ionization() from
>> ionization_lib and you can get lots of ionization data on a per-cell basis
>> (I believe this is where the data in the profile output I mentioned above
>> actually comes from). Word of warning though: that routine does
>> occasionally give negative ionization fractions (or at least it did last
>> time I used it), so I'm not sure how accurate it is in all cases.
>>
>> Hope that helps.
>>
>> Cheers,
>>
>> Matthew
>>
>> ------------------------------
>> *From:* Jing Luan [jingluan.xw at gmail.com]
>> *Sent:* 27 June 2017 16:01
>> *To:* RICHARD H D TOWNSEND
>> *Cc:* mesa-users at lists.sourceforge.net users
>> *Subject:* Re: [mesa-users] ionization fraction or kap table ?
>>
>> Thank you very much, Rich. It is very useful :-) :-)
>>
>> Sincerely,
>> Jing
>>
>> On Mon, Jun 26, 2017 at 9:27 PM, RICHARD H D TOWNSEND <
>> townsend at astro.wisc.edu> wrote:
>>
>>> Hi Jing —
>>>
>>> > On Jun 24, 2017, at 9:55 AM, Jing Luan <jingluan.xw at gmail.com> wrote:
>>> >
>>> > Dear mesa users,
>>> >
>>> > 1, Are there parameters in mesa that tells the ionization fraction of
>>> (HI to HII) and of (HeI to HeII) please? I search around
>>> mesa/star/public/star_data.inc, but did not find any. But maybe I miss
>>> something there.
>>> >
>>>
>>> I would suspect not. Nowadays, with tabulated EOS’s, it is unusual to
>>> actually solve the Saha equation during a stellar evolution calculation.
>>> However, MESA *can* tell you the free electron number density, and so you
>>> could calculate the ionization fractions yourself, using the Saha equation
>>> (for this, I suggest you ignore excited states of the H/He).
>>>
>>> > 2, For calculating kappa mechanism due to H or He opacity bumps for
>>> driving stellar oscillation, which kappa table and eos table should be
>>> adopted please? The default in mesa-r8118 are
>>> >
>>> > kappa_file_prefix = 'gn93'
>>> >
>>> > eos_file_prefix = 'mesa'
>>> > eosDT_Z1_suffix = '_CO_1'
>>> > eosPT_Z1_suffix = ‘_
>>> > CO_1'
>>> >
>>>
>>> For the blue edges of the classical (Cepheid) instability strip, plotted
>>> in Fig. 14 of Paxton et al (2015), I used:
>>>
>>> initial_zfracs = 6 ! Asplund et al. (2009)
>>> kappa_file_prefix = 'a09' ! Asplund et al. (2009)
>>>
>>> …in the &star_job namelist, and
>>>
>>> initial_Y = 0.2703 ! Asplund et al. (2009) / proto-solar
>>> initial_Z = 0.0142 ! Asplund et al. (2009) / proto-solar
>>>
>>> …in the &controls namelist. I expect the metallicity is less important
>>> to driving classical Cepheid pulsations than the relative H/He abundances.
>>>
>>> cheers,
>>>
>>> Rich
>>>
>>> > Many thanks 😊😊😊😊
>>> >
>>> > Sincerely,
>>> > Jing
>>> > ------------------------------------------------------------
>>> ------------------
>>> > Check out the vibrant tech community on one of the world's most
>>> > engaging tech sites, Slashdot.org! http://sdm.link/slashdot______
>>> _________________________________________
>>> > mesa-users mailing list
>>> > mesa-users at lists.sourceforge.net
>>> > https://lists.sourceforge.net/lists/listinfo/mesa-users
>>>
>>>
>>
>> ------------------------------------------------------------
>> ------------------
>> Check out the vibrant tech community on one of the world's most
>> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
>> _______________________________________________
>> mesa-users mailing list
>> mesa-users at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/mesa-users
>>
>>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20170629/54507cca/attachment.html>