Re: [mesa-users] AGB convergence problem

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

Hi,

Let me 2nd Hector's comment -- learn to use pgstar and keep it running during the time your model is climbing up from the horizontal branch.  See what is happening when it starts to run into problems.  Trying to figure out whats gone wrong by looking at the wreckage when it gives up with convergence problems is not a useful approach!  

btw: great to have mesa in Ireland! ;)  please take a moment to let Frank know details so we can be sure you are on the next MESA map

Good luck,
Bill


Take a look at the maps below to see the locations of MESA users. To have your location added, email Frank Timmes.





On Jul 21, 2016, at 11:09 AM, LAURA A. BOYLE wrote:

> Dear all,
> 
> I have a problem regarding the evolution of low and intermediate mass stars through the AGB phase. For example in a 2Msun star what I have done is create a pre-main sequence model in order to use metallicity, Z = 0.01 and then evolve the star with default parameters through the main sequence through to the end of the horizontal branch, at which point I stop the model. Using the final point of this model I begin to run from end of horizontal branch with the aim of going to the end of the AGB. I am only interested in retrieving the history.data file for the AGB output.... and I am most importantly interested in the AGB tip luminosity.
> 
> The problem I am having is that the model seems to get stuck somewhere possibly near the AGB tip, and I am not even sure if it ever really reaches it. At this point I either stop the model manually or wait until it eventually (after about 12 hours!) stops due to a "convergence" error because the timesteps have gotten too small. 
> 
> Is there a stopping control to have MESA stop at the AGB-tip or before it gets stuck in this slow low-timestep phase? I have read that increasing the mass-loss rate near this point can help MESA remove the envelope, but I think in that case the evolution has surpassed the point I need to look at, I would like to stop before the problem arises.
> 
>  
> 
> Laura Boyle (Ph.D. Student)
> Room 139,
> Centre for Astronomy,
> School of Physics,
> NUI Galway
> 
> Telephone: +353 91492992
> 
> 
> Kindly Funded by The Irish Research Council
> www.research.ie
> 
> 
> 
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