[mesa-users] bad angular_momentum_j

[Kenny Van]

Hi Pablo,

Sorry for the late reply. I would be under the impression that I'm always
capturing the same convective zone. I haven't had a chance to make a super
thorough check but looking at the kippenhahn diagrams produced by this test
the conv_mx1 and conv_mx2 check should pull the outer convective envelope.
Once the star has dropped to 0.26 msun it shouldn't have much of a outer
convective envelope.

The check I made there was due to a numerical issue I ran into before where
some of the outputs would be -1e-99. I just needed to get rid of those.

On 12 August 2016 at 22:49, Pablo Marchant <pamarca at gmail.com> wrote:

> You are trying to get the turnover time for an outer convection zone,
> right? I see you take the sum of dr/conv_vel for radii above
>
> envelope_edge = max(s% conv_mx1_bot_r, s% conv_mx2_bot_r)
>
> you should be careful as small convective regions can turn on and off, and
> that can cause a sudden change on your turnover time. Do you know if you
> are capturing the same convective zone all the time? What is the mass
> coordinate corresponding to that? In particular, you have a system where,
> if I have it right, a 1 msun star at TAMS is stripped by a mysterious
> object (I'll guess a NS as you chose a mass of 1.4 msun) and goes down to
> 0.26 msun. Does this star even have a relevant outer convective zone left
> at this point?
>
> Check the structure of your star to see if what you are doing makes sense,
> doing some Kippenhahn plots should be useful. In this note, it is very
> useful if you actually summarize what is your initial setup, what your
> model is doing, what you believe it should be doing, and at which point its
> crashing,
>
> Also quick comment
>
> #########################################################
>          if (turnover_time .lt. 0.0) then
>              turnover_Time = 2.8d6
>             ! If the turnover time is less than zero, set it so that the
>             ! MB tt boost is 1
>          end if
> #########################################################
>
> Why do you create a check to silently ignore something that should not
> happen?
>
> On Sat, Aug 13, 2016 at 3:32 AM, Kenny Van <kvan at ualberta.ca> wrote:
>
>> Hi Josiah,
>>
>> Yes. there are sometimes oscillations in the results. I was trying to
>> take the sum of all of the dr/conv_vel as the integral of dr/conv_vel in my
>> code.
>>
>> On 12 August 2016 at 19:30, Josiah Schwab <jwschwab at berkeley.edu> wrote:
>>
>>> Hi Kenny,
>>>
>>> Isn't this the only way to calculate the convective turnover time
>>>> though? It's normally calculated as
>>>>
>>>
>>>>
>>> integral from surface of star to bottom of convective envelope dr /
>>>> convective velocity.
>>>>
>>>> I'm not sure how else to calculate this value except by taking
>>>> dr/conv_vel in MESA
>>>>
>>>
>>> Bill's point is that dr/conv_vel itself isn't a physical quantity,
>>> because that's just a statement about the resolution.  The integral of
>>> dr/conv_vel is a physical quantity, and should be resolution-independent in
>>> a converged simulation.  Is the integral having large model-to-model jumps?
>>>
>>> Josiah
>>>
>>>
>>
>>
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>
>
> --
> Pablo Marchant Campos
> M.Sc on Astrophysics, Universidad Católica de Chile
> PhD student, Argelander-Institut für Astronomie
>
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