[Mesa-users] Nonphysical behavior of outermost envelope of rapidly rotating stars

[Aldo Serenelli]

Hi Tomek,

I see what you meen, thanks. That'd be a different issue indeed.

Best,

Aldo




On 29/07/2020 14:17, Tomasz Plewa wrote:
> Great - thanks, Aldo.
>
> I said I suspect a model failure, meaning the solution entering a 
> regime it was not designed for, because neither resolving my models 
> better numerically nor changing available physics options stabilized 
> solutions.
>
> If I recall correctly, my impression was that failing models were 
> evolving toward rotational ejection of the envelope, or some parts of 
> it,  but the algorithm was not capable of handling such situations.
>
> Tomek
> --
>> On Jul 29, 2020, at 4:18 AM, Aldo Serenelli <aldos at ice.csic.es> wrote:
>>
>>  Hi Tomek, Larry,
>>
>> I've passed the question to M. Asplund about density inversions in 
>> his 3D hydro, and they also happen in his full RHD 3D models, related 
>> to ionization of H and change in molecular weight. This coincides 
>> with regions of quick (spatially) opacity variations, in the 
>> regionwhere convective velocities are largest (whichis probably 
>> around the temperatures in which Larry finds it). Martinfinds other 
>> situations in which they also occur (hotter dwarfs, in the direction 
>> of that old 1970 reference).
>>
>> Best,
>>
>> Aldo
>>
>>
>>
>>
>>
>>
>> On 29/07/2020 01:11, Tomasz Plewa via Mesa-users wrote:
>>> Thank you, Larry. I suspected the observed runaways to be related to 
>>> the abnormal structure of the outer layers. This is good news.
>>>
>>> The bad news is I was never successful with resolving this problem 
>>> by tweaking great many readily accessible runtime parameters. 
>>> Although Aldo might onto something re convection, my experience 
>>> makes me believe the model (physical, numerical) needs modified.
>>>
>>> My cases were limited to massive, fast rotating, mass losing RSGs. I 
>>> will be eager to return to those studies, of course!
>>>
>>> Tomek
>>> --
>>>
>>>> On Jul 28, 2020, at 4:23 PM, Larry Molnar <lmolnar at calvin.edu> wrote:
>>>>
>>>> 
>>>>
>>>> Here are the plots a second time scaled to zoom in on the outer 
>>>> layers only.
>>>>
>>>> *From:* Larry Molnar <lmolnar at calvin.edu>
>>>> *Sent:* Tuesday, July 28, 2020 4:17 PM
>>>> *To:* Tomasz Plewa <tplewa at fsu.edu>
>>>> *Cc:* Pablo Marchant <pamarca at gmail.com>; mesa-users at lists.mesastar.org
>>>> *Subject:* RE: [Mesa-users] Nonphysical behavior of outermost 
>>>> envelope of rapidly rotating stars
>>>>
>>>> Here are some sample log(rho)-log(T) plots for the case of M = 1.0 
>>>> Msun, Omega/Omega_crit (initial) = 0.42. The excursion to low 
>>>> surface temperature/large radius occurred in profiles 146-225. My 
>>>> samples include before, during and after the excursion.
>>>>
>>>> I see that the density briefly **increases** with increasing radius 
>>>> in the outermost layers of the suspect profiles.
>>>>
>>>> *From:* Tomasz Plewa <tplewa at fsu.edu>
>>>> *Sent:* Monday, July 27, 2020 4:58 PM
>>>> *To:* Larry Molnar <lmolnar at calvin.edu>
>>>> *Cc:* Pablo Marchant <pamarca at gmail.com>; mesa-users at lists.mesastar.org
>>>> *Subject:* Re: [Mesa-users] Nonphysical behavior of outermost 
>>>> envelope of rapidly rotating stars
>>>>
>>>> Larry -
>>>>
>>>> Can you show the log(rho)-log(T) plot, please? How the density 
>>>> looks like in the surface layers?
>>>>
>>>> Tomek
>>>>
>>>> <190LogRhoLogT.png>
>>>> <220LogRhoLogT.png>
>>>> <250LogRhoLogT.png>
>>>> <130LogRhoLogT.png>
>>>> <160LogRhoLogT.png>
>>>
>>>
>>> _______________________________________________
>>> mesa-users at lists.mesastar.org
>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>>
>>

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