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

[Bill Paxton]

One more thing --- the particular failure mode for the run you sent is related to the convergence problem.
During an attempt to find a solution, the newton iteration has gotten horribly confused and has created a
cell with logT = 3.0 and logRho = 228.3 -- that's a rather large density!   The eos not unreasonably gave 
back junk leading to a NaN.  Rather than doing a stop (which is what happened), the code was supposed
to reject the candidate solution and try again.   This is fixed in the newest version (2483).  But as I said
in the previous email, that's just a symptom of a deeper problem that remains unsolved.

-B








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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