[mesa-users] Late AGB evolution

[Jeff Andrews]

Craig, thank you for pointing out that review. It looks like it's exactly
what I need.

Falk, I'm particularly interested in how different AGB wind prescriptions
affect the resulting WD mass. Since I'm not too interested in s-process
surface abundances, I was hoping to be able to get away with using
approx21.net, but it looks like the bottleneck is with the hydro solvers
anyway, not the reaction network. I haven't checked yet, but maybe this is
due to the large radial velocities you are describing. I'd be happy to hear
any ideas about potential work-arounds.

-Jeff



On Fri, May 23, 2014 at 11:52 AM, Craig Wheeler
<wheel at astro.as.utexas.edu>wrote:

> Jeff,
>
> You might have a look at this for background.
>
> http://adsabs.harvard.edu/abs/2000ARA%26A..38..573W
>
> Craig
>
>
>
> On 5/23/14 2:45 AM, Falk Herwig wrote:
>
>> Jefff, this is a know issue. It becomes worse for stars of higher Z and
>> higher mass (2Msun for Z=Z_sun would maybe already be problematic), and if
>> you are resolving all the details of the TP-AGB mixing processes that
>> produce wonderful things like C stars at the right (low) luminosity, and
>> C13 pockets for the s process and so on. If you turn the hydro terms on you
>> will likely see that MESA would like to do very large radial motions which
>> eventually become even supersonic. My interpretation of this is that the
>> condition of the stellar envelope at this point really becomes
>> non-spherical and hydrodynamic, and that this presents another case of "you
>> should really stop 1D and do 3D instead" - which of course is not practical
>> for some goals. One would need to resort to "stellar engineering tricks" at
>> this point, to see if one can reach whatever the science goals of the
>> project are. For certain science goals there are some ideas around for
>> appropriate "tricks". Help to implement them would be appreciated, but it
>> is not clear that they would solve your problem without knowing what
>> exactly your goal is.
>>
>> Best, Falk.
>>
>> On 2014-05-22, at 10:29 PM, Jeff Andrews wrote:
>>
>>  Hello all,
>>>
>>> I'm working on a project testing how different wind mass loss
>>> prescriptions and rates affect the evolution from an AGB star into a white
>>> dwarf. I've run into a problem evolving the system through loss of the
>>> entire hydrogen envelope. It seems like the solvers have real trouble here
>>> - as more hydrogen is removed, the time steps decrease due to "newton
>>> iters" until they are too small to continue. This happens well before the
>>> star becomes a WD. I've tried everything I can think of to help out the
>>> solvers, but the stars still don't become WDs.
>>>
>>> I'm using MESA version 6208 with the current SDK. I'm attaching my
>>> inlist to evolve a 4 solar mass star.
>>>
>>> Has anyone tried to do something similar? Any help from the community
>>> would be really appreciated.
>>>
>>> -Jeff
>>> <inlist_4.0M_WD>--------------------------------------------
>>> ----------------------------------
>>> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
>>> Instantly run your Selenium tests across 300+ browser/OS combos.
>>> Get unparalleled scalability from the best Selenium testing platform
>>> available
>>> Simple to use. Nothing to install. Get started now for free."
>>> http://p.sf.net/sfu/SauceLabs_______________________________
>>> ________________
>>> mesa-users mailing list
>>> mesa-users at lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/mesa-users
>>>
>> --
>> Falk Herwig
>> Dept of Physics&  Astronomy, U of Victoria
>>
>> fherwig at uvic.ca, tel: +1 (250) 721-7743
>>
>>
>>
>>
>> ------------------------------------------------------------
>> ------------------
>> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
>> Instantly run your Selenium tests across 300+ browser/OS combos.
>> Get unparalleled scalability from the best Selenium testing platform
>> available
>> Simple to use. Nothing to install. Get started now for free."
>> http://p.sf.net/sfu/SauceLabs
>> _______________________________________________
>> mesa-users mailing list
>> mesa-users at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/mesa-users
>>
>
> --
> J. Craig Wheeler
> Department of Astronomy
> 2515 Speedway, Stop C1400
> Austin, TX 78712-1205
> 512-471-6407
> http://www.as.utexas.edu/~wheel
> http://ebooks.cambridge.org/ebook.jsf?bid=CBO9780511536625
> http://www.smashwords.com/books/view/127749
> http://www.smashwords.com/books/view/178104
> http://www.amazon.com/The-Krone-Experiment-ebook/dp/B008Y6L3VW
> http://www.amazon.com/Krone-Ascending-ebook/dp/B00926QEGW
> http://www.amazon.com/The-Q-Man-1-ebook/dp/B00AFKJYKC
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20140523/6d518c8a/attachment.html>