[Mesa-users] bad dq error

[Jeremy Sakstein]

Thanks both,

I changed this to 4d5 and it seems to have solved the problem.

Thanks Josiah, I am actually setting standard_cgrav = 1.03*standard_cgrav
in extras_controls since other_cgrav seems to cause problems later on. I
was on the way to trying to change this after a few model steps but I will
test this pre_MS_T first.

Cheers,

Jeremy


On Fri, Jul 10, 2020 at 10:25 AM Pablo Marchant <pamarca at gmail.com> wrote:

> 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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