[Mesa-users] Creating a Highly Irradiated Super-Earth

[Bill Paxton]

Hi Brian,

I’m taking a look and will let you know what I find.

b


> On Jan 24, 2020, at 11:53 AM, Brian Jackson <bjackson at boisestate.edu> wrote:
> 
> I've conducted additional experiments, and I think I'm starting to see
> what the issues might be.
> 
> I've attached inlists and a model for a slightly different approach.
> The model calculation behaves fine until about 4 Gyrs out, when the
> timestep suddenly plunges and the code fails to complete the run. For
> some reason, the central degeneracy parameter goes haywire shortly
> before the run ends -- see attached History_Plot.png.
> 
> Looking at the 2011 MESA instrument
> (https://ui.adsabs.harvard.edu/abs/2011ApJS..192....3P/abstract), it
> seems the model core may be nearing a transition in the equation of
> state (log(density) = -0.19, log(temp) = 3.79 -- see attached Figure
> 1). Is there a reason why that transition would severely and abruptly
> modify the degeneracy parameter? Is there a way to smooth this
> evolutionary phase?
> 
> Or have I completely misunderstood what's going on?
> 
> Thanks,
> Brian
> 
> On Wed, Jan 22, 2020 at 5:58 PM Brian Jackson <bjackson at boisestate.edu> wrote:
>> 
>> Dear MESA Users,
>> I am still struggling to create highly-irradiated super-Earths using MESA.
>> 
>> I have attached the inlists and saved models I'm using to create a
>> 20-Earth mass planet with an envelope mass fraction of 20% (i.e., a
>> core mass of 16 Earth masses) and an irradiation 20 times Earth's
>> (i.e., 2.72e7 ergs/s/cm^2).
>> 
>> I attempt to create the planet by irradiating a gas giant planet and
>> then relaxing the mass down to my desired mass. (I've found doing it
>> the other way around leads to badness.) I've tried tweaking lots of
>> settings, but nothing seems to work. In the end, I wind up with a
>> timestep below the suggested minimum of 9.9999999999999995D-07.
>> 
>> I am using Mac OS 10.13.1, MESA 11701, and the most recent version of
>> the SDK (August 30 2019).
>> 
>> Please forgive me if I forgot any required information.
>> 
>> Thanks,
>> Brian
> <inlist><inlist_pgstar><history_columns.list><LF14_planet_relaxedM_20_ME_10-percent.mod><Paxton2011_Fig1.png><History_Plot.png>_______________________________________________
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