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

[Aldo Serenelli]

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>
>
>
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