[Mesa-users] Using make_o_ne_wd to prepare some white dwarf models

Mon Jul 23 00:53:02 EDT 2018

it is good to be aware of the default settings. it is even better to know exactly 
what a setting accomplishes. it is also unnecessary to reset the default flags 
to their default values in one's inlist, which is what you appear to be doing.

my advice is leave the default settings alone unless one has a good understanding 
of what a setting does and a good physical or numerical rationale for wanting/needing 
to changing it.

by leaving the default settings for the eos alone, you will get the current best eos. 
this is broadly similar to the figure shown in the 2011 mesa I instrument paper 
but different in detail.

fxt

> On Jul 22, 2018, at 9:00 PM, LAM Yi Hua <lamyihua at gmail.com> wrote:
> 
> Dear Frank,
> 
> 
> >defaults are set and stored in $MESA_DIR/star/defaults/ , and may also be read online at the mesa website. for example,
> >http://mesa.sourceforge.net/star_job_defaults.html#eos_controls 
> >and 
> >http://mesa.sourceforge.net/star_job_defaults.html#kap_controls . 
> 
> Thanks!!!
> Yes, I did notice these few related files like
> $MESA_DIR/star/defaults/star_job.defaults
> $MESA_DIR/star/defaults/controls_job.defaults 
> 
> 
> I suppose that setting these few flags to be true and maintaining their associated default limits, and also without changing EOS flags in controls.default, we will get a coverage of EOS presented in Figure 1 and described in Section 4.2 of Paxton et al ApJS 192, 3 (2011).  
> 
>       set_HELM_SCVH_lgTs = .true.       < I suppose we just need to set it to be true in the inlist file, then the following default limits below will be automatically set.
>       logT_low_all_HELM = 2.2d0         < And I suppose the same situation happens on: set_HELM_OPAL_lgTs, set_logRho_OPAL_SCVH_limits, set_eos_PC_parameters, set_other_HELM_flags
>       logT_low_all_SCVH = 2.3d0         <
> 
>       set_HELM_OPAL_lgTs = .true.       < 
>       logT_all_HELM = 7.7d0
>       logT_all_OPAL = 7.6d0
> 
>       set_logRho_OPAL_SCVH_limits = .true.  < 
>       logRho1_OPAL_SCVH_limit = 2.6d0
>       logRho2_OPAL_SCVH_limit = 2.5d0
> 
>       set_eos_PC_parameters = .true.        < 
>       mass_fraction_limit_for_PC = 1d-2
>       logRho1_PC_limit = 3.7d0
>       logRho2_PC_limit = 2.8d0
>       log_Gamma_all_HELM = 1.60206d0
>       log_Gamma_all_PC = 1.90309d0
>       PC_min_Z = 0.999d0
> 
>       set_other_HELM_flags = .true.          < 
>       HELM_include_radiation = .true.
>       HELM_always_skip_elec_pos = .false.
>       HELM_always_include_elec_pos = .true.  < I set this to be true.
> 
>       eosDT_use_linear_interp_for_X = .true.     < The default setting in make_o_ne_wd
>       eosDT_use_linear_interp_to_HELM = .false.  < The default setting in $MESA_DIR/star/defaults/star_job.defaults 
> 
> Please let me know if I am wrong... 
> Thanks... :)
> 
> 
> 
> best regards,
> 
> Yi Hua, LAM
> -- CaTCh EVEry SiNGle OppORtuNItY WhEN U r StILl alIVe -- 
> ---- Success Belonged To Those Who's Willing To Strive For It ----
> 
> 
> On Sun, Jul 22, 2018 at 7:16 AM Francis Timmes <fxt44 at mac.com> wrote:
> dear yi,
> 
> nice to see you are getting started with mesa.
> i'll take two of your ten questions.
> 
> > If we would like to use the default EOS and opacity defined in Paxton et al MESA-steering paper [Astrophys. J. Suppl. 192 (2011) 3], do we set the EOS and opacity as what are defined in the default inlist of make_o_ne_wd as below? [Question 7]
> > 
> >       eos_file_prefix = 'mesa'
> >       kappa_file_prefix = 'gs98'
> > 
> > If this is not the correct way, may I know how to define the default EOS and opacity?  [Question 8]
> 
> defaults are set and stored in $MESA_DIR/star/defaults/ ,
> and may also be read online at the mesa website. for example,
> http://mesa.sourceforge.net/star_job_defaults.html#eos_controls 
> and 
> http://mesa.sourceforge.net/star_job_defaults.html#kap_controls .
> 
> fxt
> 
> 
> 
> 
> 
> 
> 
> > On Jul 21, 2018, at 4:44 AM, LAM Yi Hua via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> > 
> > Dear MESA community,
> > 
> > Recently, I'd like to test some reactions associated with nova outbursts using MESA-r10398 and MESA-sdk (revision 245). [Hopefully, older MESA-sdk version won't affect the simulation.] So, most probably, the suitable white dwarf (WD) model for testing the reactions should be ONe WD, but not CO WD.
> > 
> > I have some questions to ask the community.
> > 
> > FIRST step: 
> > I used the "make_o_ne_wd" test_suite to prepare some simple white dwarf models. 
> > For the first test, the simulation of this default model stopped at 
> > 
> > model 592
> > termination code: xa_central_upper_limit
> > 
> > Then, I commented these two lines in the &star_job of inlist_make_o_ne_wd file:
> > 
> > !      xa_central_upper_limit_species(1) = 'ne20'
> > !      xa_central_upper_limit(1) = 0.35d0
> > 
> > I ran the simulation again, but it stopped at 
> > 
> > model 840
> > stopping because of problems -- too many retries
> > terminated evolution: nonzero_ierr
> > termination code: max_number_retries
> > 
> > Perhaps, someone can identify the problem.
> > 
> > Anyway, it is not a big deal. Although the HR diagram shown in Figure 1 of make_o_ne_wd/docs/make_o_ne_wd.pdf could not be reproduced, at least I can confirm that my installation is successful, and a partial HR diagram was produced from log Teff=3.9 up to 5.5 and log L/Ldot = 3.7 up to 4.5. Also, I do not think the problem is due to older MESA-SDK version. After that, I tested the make_o_ne_wd test_suite of MESA-r8118 with MESA-sdk (revision 245). This simulation ran successfully until it terminated with log_L_lower_limit. The produced HR diagram make_o_ne_wd (MESA-r8118) is not exactly the same as the partial HR diagram of MESA-r10398, in particular there is a kink from Teff=3.9 to 4.2 in the HR diagram of make_o_ne_wd of MESA-r8118 during the post-AGB stage. In fact, the HR diagram shown in Figure 1 of make_o_ne_wd.pdf also has that kink. 
> > 
> > As long as we can still produce a WD model eventually, shall we change some settings to eliminate/reduce such kink? [Question 1]
> > 
> > Both HR paths produced from MESA-r10398 and MESA-r8118 show some oscillation at the end of post-AGB stage, around Teff=5.1 to 5.4 and log L/Ldot = 4 to 4.4. If we can still produce a WD model eventually, shall we change some settings to eliminate/reduce such oscillation? [Question 2]
> > 
> > 
> > SECOND step:
> > I extend the list of isotopes and reactions stated in co_burn_plus.net which is used by make_o_ne_wd. The newly extended list includes 78 isotopes (from 1H up to 40Ca) and associated 480 reactions. These 78 isotopes were also included by Politano et al. (1995) and Weiss et al. (1990). Also, I made a few changes to inlist_make_o_ne_wd:
> > 
> > ************************************************************** 
> > &star_job 
> > eosDT_use_linear_interp_for_X = .true. < This flag does not exist in MESA-r8118. I compare results produced by MESA-r10398 with and without this flag.
> >                                        < I found that implementing this linear interpretation increases mass loss.
> >                                        < However, if I switch it to be .true. for initiall mass 9.5 Mdot, it causes the problem of dt < min_timestep_limit=1d-20 at model 1070.
> >                                        < Perhaps, this is not the reason causing the problem of dt < min_timestep_limit .
> >                                        < There is no problem for initial_mass=9.8 or 9.7. Maybe, there are some settings associated with the change of initial mass.
> > 
> > !      change_D_omega_flag = .true.  < These flags do not exist in MESA-r8118. I switch off these flags because they do not smoothen the post-AGB HR path. 
> > !      new_D_omega_flag = .true.     < Bill Paxton said he is "experimenting a new scheme to reduce the noise in the rotational mixing diffusion coefficients 
> >                                      < by doing spatial and temporal smoothing." 
> >                                      < The default flags are .false.
> > 
> > &controls
> >        max_number_retries = 500                     < I increased it for more attempts solving the hydro-Newton equation before termination.
> >        max_model_number = 6000                      < 
> > 
> > !      xa_central_upper_limit_species(1) = 'ne20'   < I switched off these two flags due to reason mentioned above.
> > !      xa_central_upper_limit(1) = 0.35d0           <
> > 
> >       min_timestep_limit=1d-20                      < 
> >       log_L_lower_limit = 0                         < 
> > 
> > **************************************************************
> > 
> > I did not apply any "stellar engineering" (trick) during mass loss at end-AGB stage when star mass drops from 10 Mdot to 5.5 Mdot.
> > 
> > With defining initial_mass= 10, the simulation stops at log_L_lower_limit = 0 and eventually, the star becomes a white dwarf with 16O and 20Ne rich core, and log_cntr_T=8.08 (center temperature). The mass fraction of 16O is 0.545 from 0 to 1.195 Mdot, whereas the mass fraction of 12C is about 0.427 at the mass coordinate of 1.195 Mdot and drops to around 0.010 at the mass coordinate of 1.175 Mdot. I suppose the small mass region with high fraction of 12C is the so-called C-rich buffer zone separating the bottom of the convective envelope from the WD surface according to some literatures.
> > 
> > If I am not mistaken, to further cool the WD and to make a naked WD, we need to remove this buffer zone first, otherwise the code cannot proceed due to unresolved hydro-Newton equation causing termination of dt < min_timestep_limit=1d-20. I did try to cool the WD (restart the simulation) after the stage of log_L_lower_limit = 0 and log_cntr_T=8.08 (center temperature). But it does not work, it keeps stopping with limit of dt < min_timestep_limit=1d-20, even I tried to change some settings.
> > 
> > I think, to proceed the cooling of a WD to the desired temperature, artificially removing this buffer zone will be more effective than changing various settings of simulation.
> > To do so, do we just simply change the mass fractions of 12C and other isotopes in the freshly saved *.mod and *.data files to 0 after the simulation stop?  [Question 3]
> > Do we have to rescale the dq (fraction of total mstar in cell) column?  [Question 4]
> > And, how about other physical properties recorded in columns of lnd, lnT, lnR, L, omega, etc. do we need to follow some procedure/method to change them?  [Question 5]
> > 
> > Besides, I did try with initial_mass=9.5d0, but the simulation stops at model 1120 due to unresolved hydro-Newton equation and finally it reached dt < min_timestep_limit=1d-20. There is no problem to set initial_mass=9.8d0. Perhaps, there are some settings directly related to the change of initial star mass. May I know the best way to overcome this problem?  [Question 6]
> > 
> > 
> > If we would like to use the default EOS and opacity defined in Paxton et al MESA-steering paper [Astrophys. J. Suppl. 192 (2011) 3], do we set the EOS and opacity as what are defined in the default inlist of make_o_ne_wd as below? [Question 7]
> > 
> >       eos_file_prefix = 'mesa'
> >       kappa_file_prefix = 'gs98'
> > 
> > If this is not the correct way, may I know how to define the default EOS and opacity?  [Question 8]
> > 
> > 
> > If I am not mistaken, the default reaction library of MESA-r10398 is JINA REACLIB, do we still need to include these few lines below in inlist file?  [Question 9]
> >       set_rates_preference = .true.
> >       new_rates_preference = 2
> >       set_rate_c12ag = 'jina reaclib'
> >       set_rate_n14pg = 'jina reaclib'
> >       set_rate_3a = 'jina reaclib'
> > 
> > 
> > May I know the best option for the below reactions associated with 12C? [Question 10] 
> > Is there anyone would like to share her/his experience?
> > 
> >          ! + `'CF88_basic_1212'` : the single rate approximation from CF88.
> >          ! + `'CF88_multi_1212'` : combines the rates for the n, p, and a channels.
> >          ! c12(c12,n)mg23, c12(c12,p)na23, and c12(c12,a)ne20 and
> >          ! uses neutron branching from dayras, switkowski, and woosley, 1976.
> >          ! + `'G05'` : based on Gasques, et al. Phys Review C, 72, 025806 (2005)
> > 
> >          set_rate_1212 = ''
> > 
> > 
> > 
> > Thanks for your precious time...
> > Your responses are very appreciated...
> > 
> > 
> > 
> > best regards,
> > 
> > Yi Hua LAM
> > -- CaTCh EVEry SiNGle OppORtuNItY WhEN U r StILl alIVe -- 
> > ---- Success Belonged To Those Who's Willing To Strive For It ----
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> > 
> 