[Mesa-users] Relaxing Entropy from Profile Pairs?

[Charles Gibson]

Thank you so much! This helped me out a ton. I was able to successfully
relax these data from both a MESA run and a StarSmasher run.

I don't think that I was too sure of what I was asking for with q values. I
should have asked how MESA determines how many shells should be in a
model, and how it divides those shells. It doesn't look like they are
divided into equal mass or equal radius. Is there a table or equation that
I can use to see how these shells may be spaced?

Thank you again,
Charlie

On Sun, Apr 2, 2023 at 3:50 PM Ebraheem Farag <ekfarag at asu.edu> wrote:

> Hello Charles,
>
> See : get_entropy_for_relax_from_eos
> <https://docs.mesastar.org/en/release-r22.11.1/reference/star_job.html#get-entropy-for-relax-from-eos>
>
> Try setting the following in your &starjob section of your inlist:
>
> get_entropy_for_relax_from_eos = 'eosDT'
> -------------------------------------------
> "when generating the number of shells and each of their q values (how
> much mass is located outside the shell), is there a specific formula that
> determines how I should determine those values?"
>
> see below also from from star_job.defaults, get_entropy_for_relax_from_eos
> <https://docs.mesastar.org/en/release-r22.11.1/reference/star_job.html#get-entropy-for-relax-from-eos> (in
> mesa-r22.11.1), please verify against the r10398 defaults:
>
> When any of the eos* options is used, then each line in the input file
> must contain three columns instead of two, specifying the values of the two
> thermodynamic variables used in the order specified above. So, for example,
> when using ‘eosDT’ the format of the input file is
>
> 1st line: num_pointsthen 1 line for for each point where define desired entropyxq entropyxq = fraction of xmstar exterior to the pointwhere xmstar = mstar - M_centerentropy = specific entropy in units of erg/gr/K
>
> -------------------------------------------
>
> I hope this helps!
> -EbF
>
>
> On Sun, Apr 2, 2023 at 10:48 AM Charles Gibson via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
>> Hello,
>>
>> I am an undergraduate student working on taking a star evolved in MESA
>> from an SPH code (StarSmasher) and inputting it back into MESA to observe
>> its evolution. I have been working in the directory
>>
>> star/test_suite/relax_composition_j_entropy
>>
>> to ensure that I can accurately recreate a model from a previous mesa
>> run. So far, I have succeeded in replicating the star's evolution through
>> this method.
>>
>> However, the StarSmasher simulations that I am using do not supply direct
>> values for entropy. I read in Appendix B of this paper
>> <https://urldefense.com/v3/__https://iopscience.iop.org/article/10.3847/1538-4365/aaa5a8*apjsaaa5a8app2__;Iw!!IKRxdwAv5BmarQ!eAVuCwomn0wLGPlCi_4SqSvQrROsX2Y_TuBprfGga0bhSO6wXIJlmJc-W0u6zBGNWJ1gv92vrZBdqqf020zJGhiz$> that
>> I can supply different pairs of profiles including (rho, T), (P_gas, T),
>> and (rho, e) in the entropy's place. These are all quantities that I can
>> easily obtain.
>>
>> When I run the relax model using (rho, T) in place of entropy, the run
>> fails when processing the entropy file. I have it formatted the same as the
>> entropy file, but with three values on each line instead of two. Is there a
>> variable in the inlist that I have to alter to indicate that I am changing
>> the type of supplied entropy data? If it helps, I am using v10398.
>>
>> Additionally, as a side question, when generating the number of shells
>> and each of their q values (how much mass is located outside the shell), is
>> there a specific formula that determines how I should determine those
>> values? I haven't gotten to the point where I am extracting values from
>> StarSmasher yet, but once I do, I want to make sure that I determine the
>> values so that MESA can effectively read them.
>>
>> Thank you,
>> Charlie
>> _______________________________________________
>> mesa-users at lists.mesastar.org
>>
>> https://urldefense.com/v3/__https://lists.mesastar.org/mailman/listinfo/mesa-users__;!!IKRxdwAv5BmarQ!eAVuCwomn0wLGPlCi_4SqSvQrROsX2Y_TuBprfGga0bhSO6wXIJlmJc-W0u6zBGNWJ1gv92vrZBdqqf02-SGqssJ$
>>
>>
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