[Mesa-users] Reproducing Paxton et al. 2013 fig. 1

Thu Aug 8 19:24:36 UTC 2024

hi emily,

thanks for your sharing the results of your numerous experiments. i see you also posted a github issue, so that's a good.

fxt

> On Aug 8, 2024, at 4:46 AM, Emily Sandford via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> On 2024-07-12 23:05, Francis Timmes wrote:
>> hi emily,
>> yes, this is a known issue. see this thread
>> https://lists.mesastar.org/pipermail/mesa-users/2024-March/015070.html
>> and this potential workaround
>> https://lists.mesastar.org/pipermail/mesa-users/2024-April/015133.html
>> some preliminary mesa-dev investigations suggested the phenomena may
>> be due to changes since 2013 how the low temperature eos is handled.
>> if you find the problem persists, perhaps file an issue on mesa github
>> https://github.com/MESAHub/mesa .
>> fxt
>>> On Jul 10, 2024, at 8:24 AM, Emily Sandford via Mesa-users <mesa-users at lists.mesastar.org> wrote:
>>> Hello,
>>> I'm a new MESA user, attempting to use r24.03.1 to model brown dwarf and giant planet evolution. As a first step I want to reproduce the models plotted in Paxton et al. 2013 figure 1, which are initiated with create_initial_model with radius equal to 5 R_J and masses ranging from 0.2 to 20 M_J, and then evolved for 20 Gyr.
>>> The only controls enumerated in the paper are:
>>> &star_job
>>>  create_initial_model = .true.
>>>  mass_in_gm_for_create_initial_model = 3.7972d31  ! 20 m_jupiter;  m_jupiter = 1.8986d30
>>>  radius_in_cm_for_create_initial_model = 3.596d10 ! 5 r_jupiter; r_jupiter = 7.192d9
>>> / ! end of star_job namelist
>>> &eos
>>>  eosDT_file_prefix = 'mesa' ! replaces deprecated eos_file_prefix = 'mesa', as I understand it
>>> / ! end of eos namelist
>>> &kap
>>>  Zbase = 0.02d0             ! not mentioned explicitly in Paxton et al. 2013, but now seems to be necessary
>>>  kap_file_prefix = 'gs98'
>>>  kap_lowT_prefix = 'lowT_Freedman11'
>>> / ! end of kap namelist
>>> &atm
>>>  which_atm_option = 'simple_photosphere'
>>> / ! end of atm namelist
>>> &controls
>>>  initial_y = 0.27d0
>>>  initial_z = 0.02d0
>>>  mixing_length_alpha = 2.0d0
>>>  max_age = 2.0d10
>>> / ! end of controls namelist
>>> This works fine for initial mass 20 M_J; however, it fails almost immediately for initial mass <= 14 M_J (the initial model is created, but then the evolution stalls at age ~a few years). I looked at the make_brown_dwarf test suite example for inspiration, and found that adding
>>> convergence_ignore_equL_residuals = .true.
>>> allows models with initial masses down to 6.9 M_J to evolve for the full 20 Gyr without problems. However, for initial masses <= 4.8 M_J, the evolution stalls once again (at late ages--for the 4.8 M_J model, it's at 12.4 Gyr), and I don't know how to fix this. I've tried turning on the other controls used in make_brown_dwarf (mlt_make_surface_no_mixing = .false. , make_gradr_sticky_in_solver_iters = .true. , energy_eqn_option = 'dedt'), but none of them have any effect. I've also played around with the make_planets test suite example, turning off the step where an inert core is added, but with no success.
>>> The one thing that worked for the 4.8 M_J model was to adjust the initial radius downward to 2 R_J, but then that choice of radius also fails for initial masses <= 3.4 M_J (and I'm hoping there's an easier way forward than to keep hand-tuning the initial radius for every new choice of initial mass).
>>> Does anyone have advice for how to make progress from here, ideally in a way that allows me to run a suite of models at different initial masses but with the same initial radius, as with the models plotted in Paxton+2013? I'm happy to provide more detailed debugging information if it's helpful, but given that these models have successfully been run before, I'm hoping it's just a matter of choosing the right inlist settings.
>>> Thanks!
>>> Emily Sandford
>>> sandford at strw.leidenuniv.nl
>>> _______________________________________________
>>> mesa-users at lists.mesastar.org
>>> https://lists.mesastar.org/mailman/listinfo/mesa-users
> 
> Dear Frank,
> 
> Thanks for this, it was very helpful--I've done some more investigating, and I will file a github issue, but I wanted to post my findings here too in case someone else runs into the same problem in the future. My results are consistent with the hypothesis that a change to the low-EOS behavior post-r12115 (released October 2019) is responsible for the issues I was having.
> 
> (Note that, in the below, I am only testing at the specific initial mass values plotted in Paxton et al. 2013 fig 1: 20.0, 14.0, 9.8, 6.9, 4.8, 3.4, 2.3, 1.6, 1.1, 0.82, 0.57, 0.4, 0.28, and 0.2 M_J.)
> 
> In brief, I have found that:
> -Adapting the r24.03.01 make_brown_dwarf test suite case works fine for initial masses >= 1.6 M_J. At the lower end of that mass range, it is necessary to tune the initial radius downward, in line with the suggestion in this thread: https://lists.mesastar.org/pipermail/mesa-users/2024-April/015133.html . (Unfortunately, the other suggestion proffered in that thread, to change kap_lowT_prefix from 'lowT_Freedman11' to 'lowT_fa05_gs98', hasn't worked at all for me; I get instant 'failed in kap_get get_kap_from_rhoT; temp too low in integration' errors, regardless of initial mass or radius.)
> -At initial masses <= 1.1 M_J but > 0.2 M_J, the only way to make progress is to turn on irradiation to heat the outer layers of the planet and prevent temperatures from dropping below ~150K. (Thanks to Henrik Knierim for this suggestion!)
> -At initial mass = 0.2 M_J, the create_initial_model step fails, regardless of choice of initial radius or irradiation parameters. Nothing I have tried in r24.03.01 works at this mass.
> -However, reverting to MESA r12115 allows objects with initial masses >=0.2 M_J to evolve to 20Gyr without irradiation. It is necessary to set use_eosDT2 = .false. and use_eosELM = .true., as in the r12115 make_brown_dwarf test suite example.
> 
> I have attached the inlists I used for r24.03.01 (split into "create" and "evolve" steps in order to try to isolate the create_initial_model problem at extremely low masses, but without success) and for r12115 in case this is helpful to anyone.
> 
> Best,
> Emily
> <r24.03.01_inlist_create><r24.03.01_inlist_evolve><r12115_inlist_create+evolve.txt>_______________________________________________
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