[Mesa-users] Cooking a Planet

Francis Timmes fxt44 at mac.com
Tue Dec 17 00:19:45 EST 2019

i assume that you are working through roger's 2017 minilab 1 
and having trouble with step e. if so, it probably would have 
been quicker just to say that ;)

one of the changes between r9793 of the 2017 summer school
and r11701 of may 2019 is how the eos is treated by default.
mostly if you set 

     use_eosELM = .false.
     use_eosDT2 = .false.

the run will easily go to 1e11 years, reaching Teff ~ 60 k.
it is also useful to increase the mass and time resolution.
attached is a modified version of your inlist that works in r12115.


> On Dec 13, 2019, at 4:59 PM, Brian Jackson <bjackson at boisestate.edu> wrote:
> Apologies if I've been unclear: I want to set L_center = 0 so that
> there is no extra core luminosity. Have I misunderstood what that
> variable means?
> Thanks,
> Brian
> On Fri, Dec 13, 2019 at 4:07 PM Francis Timmes <fxt44 at mac.com> wrote:
>> its not clear what you expect/desire the end state to be.
>> at termination the model has LogL ~ -10, T_c ~ 6000 K, and Teff ~ 200 K.
>> fxt
>>> On Dec 12, 2019, at 9:38 AM, Brian Jackson <bjackson at boisestate.edu> wrote:
>>> Dear MESA Users,
>>> If I can trouble you all again, I have another question about modeling planets.
>>> I am trying to model a super-Earth type planet, and I have mostly
>>> followed the instructions described in Leslie Rogers's MESA tutorial
>>> from 2017. (I have, however, found they don't work perfectly, so I had
>>> to modify the approach a little.)
>>> Toward the end of the modeling sequence, I create a model with an
>>> internal luminosity using the relax_L_center scheme and evolve the
>>> model until the central entropy reaches 10 kB / baryon. The resulting
>>> model is attached (planet_evolve_29ME_9percent_10kB).
>>> Then I try to reduce the central luminosity by a large factor (1e6, as
>>> suggested by Rogers's lab) and then evolve the model for a long time,
>>> but that model fails after about 1e8 years of evolution with the
>>> following message:
>>>    stopping because of problems dt < min_timestep_limit
>>>    terminated evolution: cannot find acceptable model
>>>    termination code: min_timestep_limit
>>> I have attached the inlist that implements that calculation. I *have*
>>> found that if I reduce L_center by a smaller factor, say 50,000, the
>>> model is able to reach the desired age.
>>> Could you provide any insight or suggestions for how to reduce the
>>> central luminosity by a large factor and circumvent this issue?
>>> Ideally, I think I'd like to zero it out.
>>> I am using Mac OS 10.13.1, MESA 11701, and the most recent version of
>>> the SDK (August 30 2019).
>>> Thanks,
>>> Brian

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