[mesa-users] Slow evolution in 1.5 Msun model

Ehsan Moravveji moravveji at iasbs.ac.ir
Thu Oct 18 04:23:53 EDT 2012


Dear all,
I am running a grid of models of 1.5 to 2.5 Msun stars with v. 4589. The
star is supposed to start from the pre-MS phase, and stop after the core
He depletion once Teff < 3000.
This is supposed to be a trivial evolution as my experience with massive
tracks tell, in a sense that each model must finish in an hour or two.
However, it is over 12 hours that even the first model has not finished.
Here is the terminal output:


       step    lg_Tcntr    Teff       lg_LH     lg_Lnuc     Mass      
H_rich     H_cntr     N_cntr     Y_surf     X_avg     eta_cntr  
pts  retry
   lg_dt_yr    lg_Dcntr    lg_R       lg_L3a    lg_Lneu     lg_Mdot   
H_poor     He_cntr    O_cntr     Z_surf     Y_avg     gam_cntr  iters
bckup
        age    lg_Pcntr    lg_L       lg_LZ     lg_Psurf    lg_Dsurf  
He_poor    C_cntr     Ne_cntr    Z_cntr     Z_avg     v_div_cs    
dt_limit
__________________________________________________________________________________________________________________________________________________

      17250   8.032290   3384.687   3.079061   3.210327   1.347981  
0.819935   0.000000   0.000000   0.282155   0.427826  17.730055 
24225     81
   3.351565   6.104060   2.073604   2.480932   1.982266  -8.135194  
0.528046   0.000000   0.661732   0.014063   0.196686   4.907572      4 
   16
 2.9688E+09  22.584314   3.218765   2.081776   3.222172  -8.111061  
0.449231   0.322686   0.001312  1.000E+00  3.755E-01  0.420E-06   
varcontrol


I noticed that the number of mesh points in the model is exceedingly high!
That might be a reason for this slow evolution. True?
I am sure that I never wanted such a fine mesh spacing as in from my inlist:

         mesh_delta_coeff = 0.8
         varcontrol_target = 1d-4	! to adjust the time steps

Is this typical of low-mass stars with mesa to take too long time to finish?
Are there switches (except varcontrol_target) to speed up the evolution?
I believe there must be a way to reduce the time cost when running a grid.

Thanks
Ehsan.


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