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Re: mesa-users] creating high Z pre main sequence model
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From: Bill P. <pa...@ki...> - 2010-07-20 14:54:20
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Hi,
I'm glad you are using mesa.
The "create pre-main sequence" operation sometimes runs into cases
that are too hard for it to do -- and it looks like the Z=0.1 is such a case.
I'd suggest that you try creating what you want in a series of steps.
First, create a pre-main sequence star of the desired mass but lower Z.
Experiment to find a Z that is small enough to work.
Let the lower Z model run for 10 or 20 steps and then save it.
Now increase Z by using one of the "stellar engineering" operations
that are provided as options in the &star_job part of the inlist.
You might start by trying
change_Z = .true. ! simply changes abundances; doesn't reconverge the model.
new_Z = 0.1
That just goes into the model and changes Z in a single operation.
Give it a try. If it your model can absorb the change and keep running, great.
But if your model cannot converge when Z is changed so abruptly, try using
relax_Z = .true. ! gradually change abundances, reconverging at each step.
Hopefully one or the other of those will do the trick.
Save the new model and remove the inlist commands for changing Z.
I hope that works for you. Let me know!
Cheers,
Bill
On Jul 20, 2010, at 2:47 AM, Masanobu Kunitomo wrote:
> Dear Dr. Paxton,
>
> Hello, My name is Masanobu Kunitomo, a graduate student at Tokyo
> Institute of Technology.
>
> First, I thank you for providing the great code MESA.
>
> Today I am writing to ask you about the problem for high metallicity.
> While running the case of Z=0.1 with 'pre-main-sequence model', the
> following message was displayed;
>
> *********************************************************************************
> Revision: 2258
> Tue Jul 20 17:30:20 JST 2010
> read extra star_job inlist1 from inlist--mine
> loading eos data
> loading kap data
> finished loading
> read extra controls inlist1 from inlist--mine
>
>
> The terminal output contains the following information
>
> 'step' is the number of steps since the start of the run,
> 'lg_dt_yr' is log10 timestep in years,
> 'age_yr' is the simulated years since the start run,
> 'lg_Tcntr' is log10 center temperature (K),
> 'lg_Dcntr' is log10 center density (g/cm^3),
> 'lg_Pcntr' is log10 center pressure (ergs/cm^3),
> 'lg_Teff' is log10 surface temperature (K),
> 'lg_R' is log10 surface radius (Rsun),
> 'lg_L' is log10 surface luminosity (Lsun),
> 'lg_LH' is log10 total PP and CNO hydrogen burning power (Lsun),
> 'lg_L3a' is log10 total triple-alpha helium burning power (Lsun),
> 'lg_LZ' is log10 total burning power excluding LH and L3a and
> photodisintegrations (Lsun),
> 'lg_LNuc' is log10 nuclear power excluding photodisintegration (Lsun),
> 'lg_LNeu' is log10 total neutrino power (Lsun),
> 'lg_Psurf' is log10 surface pressure (gas + radiation),
> 'Mass' is the total stellar mass (Msun),
> 'lg_Mdot' is log10 magnitude of rate of change of mass (Msun/year),
> 'lg_Dsurf' is log10 surface density (g/cm^3),
> 'H_rich' is the remaining mass outside of the hydrogen poor core,
> 'H_poor' is the core mass where hydrogen abundance is <= 0.10E-03
> 'He_poor' is the core mass where helium abundance is <= 0.10E-03
> 'H_cntr' is the center H1 mass fraction,
> 'He_cntr' is the center He4 mass fraction,
> 'C_cntr' is the center C12 mass fraction,
> 'N_cntr' is the center N14 mass fraction,
> 'O_cntr' is the center O16 mass fraction,
> 'Ne_cntr' is the center Ne20 mass fraction,
> 'X_avg' is the star average hydrogen mass fraction,
> 'Y_avg' is the star average helium mass fraction,
> 'Z_avg' is the star average metallicity,
> 'gam_cntr' is the center plasma interaction parameter,
> 'eta_cntr' is the center electron degeneracy parameter,
> 'pts' is the number of grid points in the current model,
> 'jacs' is the number of jacobians created in the current step,
> 'retry' is the number of step retries required during the run,
> 'bckup' is the number of step backups required during the run,
> 'dt_limit' is an indication of what limited the timestep.
>
> All this and more are saved in 'LOGS/star.log' during the run.
>
> create pre-main-sequence model
> done build_pre_ms_model
> set_initial_model_number 0
> v_flag = F
> kappa_file_prefix gn93
> eos_file_prefix mesa
>
>
> __________________________________________________________________________________________________________________________________________________
>
> step lg_Tcntr lg_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_Rsurf lg_L3a lg_Lneu lg_Mdot
> H_poor He_cntr O_cntr Z_surf Y_avg gam_cntr jacs bckup
> age_yr 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
> __________________________________________________________________________________________________________________________________________________
>
> stopping because of too many backups in a row 16
>
>
>
> terminated evolution because hydro_failed_to_converge
>
> Tue Jul 20 17:39:55 JST 2010
> *********************************************************************************
>
> Would you let me know what I should do?
>
> Sincerely,
>
> Masanobu Kunitomo
>
> ----------------------------------------------
> Masanobu Kunitomo
> master's student
> Department of Earth and Planetary Sciences
> Tokyo Institute of Technology
> Email: kun...@ge...
> ----------------------------------------------
>
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