[Mesa-users] bad dq error

[Pablo Marchant]

I'm assuming you're creating stripped stars. This is just a synthetic way
to produce those, the "pre-ms" evolution you get by doing so is not
something we expect to happen in nature (ie. we don't expect a random ball
of pure helium in the universe to form a star). So as long as you can
construct your model at he-ZAMS one should be good. Of course the ideal is
to test that the choice does not actually make a difference.

Cheers

On Fri, Jul 10, 2020 at 4:22 PM Jeremy Sakstein <sakstein at hawaii.edu> wrote:

> Thanks Pablo, I will try this now.
>
> Are there any implications of this? I assume the final relaxed model will
> be the same?
>
> Cheers,
>
> Jeremy
>
> On Fri, Jul 10, 2020 at 10:20 AM Pablo Marchant <pamarca at gmail.com> wrote:
>
>> Hi Jeremy,
>>
>> the algorithm that constructs the initial model can run into that
>> problem. One possible workaround is to experiment with this option in
>> star_job
>>
>>           !### pre_ms_T_c
>>           ! Initial center temperature (must be below 1d6).
>>           ! If you have initial convergence problems creating a pre-ms
>> model,
>>           ! you might try different values for `pre_ms_T_c` -- that
>> sometimes helps.
>>
>>        pre_ms_T_c = 3d5
>>
>> Cheers
>>
>> On Fri, Jul 10, 2020 at 4:11 PM Jeremy Sakstein <sakstein at hawaii.edu>
>> wrote:
>>
>>> Hi everyone,
>>>
>>> I have a quick question.
>>>
>>> This is actually a follow up on my other thread about using other_cgrav
>>> with the ppisn test suite. For some range of masses (50-60) I am finding
>>> that I get an error message as soon as I begin:
>>>
>>> create pre-main-sequence model
>>>
>>>                                           species  mass           8
>>>  5.5000000000000007D+01
>>>
>>>                                                  bad dq          24
>>> -1.0081447620088736D-04
>>>
>>> I ran some tests and it appears that the negative dq is insensitive to
>>> the initial mass that I put in.
>>>
>>> I looked this up in star_utils.f90 and it appears that this error occurs
>>> because  there is a cell where dq is negative but I am not sure why this is
>>> happening, or what I can do to fix it.
>>>
>>> Is someone able to point me on the right track?
>>>
>>> Cheers,
>>>
>>> Jeremy
>>> _______________________________________________
>>> mesa-users at lists.mesastar.org
>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>
>>>
>>
>> --
>> Pablo Marchant Campos
>> M.Sc on Astrophysics, Universidad Católica de Chile
>> PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
>>
>

-- 
Pablo Marchant Campos
M.Sc on Astrophysics, Universidad Católica de Chile
PhD on Astrophysics, Argelander-Institut für Astronomie, Universität Bonn
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