Re: mesa-users] Massive star runs end before planetary nebula stage

[Bill P. <pa...@ki...>]

Hi Eric,

You've hit on a major open issue.  When your email arrived, I was staring at the same problem in the context of a 4 Msun case.  There seem to be some convergence problems, but I've haven't yet been able to figure out where they are coming from -- the implicit solver makes this sort of debugging very difficult since everything gets coupled to everything else.

If you are interested in the evolution at the tip of the AGB, I'm afraid I don't yet know a solution.

If you are willing to do "stellar engineering" to get at the proto-WD core under the envelope, then you can try the recipe I've included in the release -- see data/star_data/white_dwarf_models/make_a_wd.notes.

Let us all know if you figure out a way to solve the agb tip problem!  (btw: the lower masses manage to leave the tip of the agb okay -- e.g., the 1 Msun has no problem.  so there is something about the more massive envelope that is causing the trouble.)

-Bill






On Jul 1, 2010, at 10:20 AM, Eric Blais wrote:

> Hi,
> 
> I'm having trouble figuring out why the more high mass stars (5 solar masses and up) end their lives in the thermally-pulsing AGB.  From the logs, I don't see why the run ends at this point, and toying with some parameters has not solved this problem.  Perhaps someone could help me?
> 
> I've attached the inlist file.  There's nothing special there, except that I changed the net to agb.net once the star went up the AGB, but the run with the basic net ended in the same way.
> 
> I've included a saved model also.  The error happens 194 steps later and the terminal output for the last few steps is in log5M.dat.  I don't know where these variables can be found in the code, which is why I'm having trouble interpreting this error.
> 
> On the computer I use, the star is halfway up the asymptotic giant branch in 15 minutes, reaches the point of maximum luminosity on this graph in about 2 hours and then spends many hours on that last, downward curve you can see on the HR diagram.
> 
> It would be great if I could get these stars to go just a little bit further in their evolution (say, once the envelope has been reduced to a tenth of a solar mass).
> 
> Cheers,
> Eric Blais
> <log5M.dat><inlist_test><tpagb5Msun.mod><HR_5MsunNoOversh.JPG>------------------------------------------------------------------------------
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