[mesa-users] A problem in making planets

[Songhu Wang]

Hi Chris and Aaron,

Thank you for your email.
The problems have been solved when I try to use a larger initial radius.

best,
Songhu



On Tue, Jan 31, 2017 at 1:37 AM, Chris Mankovich <cmankovich at ucsc.edu>
wrote:

> Hi Songhu,
>
> I suspect Aaron's guess is probably correct, although it's hard to say
> conclusively without seeing your inlist.
>
> The routine build_initial_model (in star/private/create_initial_model.f90)
> attempts to find a hydrostatic, isentropic starting model matching the
> total mass and radius specified by the user. It does this iteratively,
> making a series of guesses for the central entropy and pressure and
> integrating the structure equations out to the surface.
>
> What this means is that small changes to the guess for central entropy or
> pressure could potentially lead to surface temperatures outside the domain
> covered by the available EOS. In particular, a 1 M_J planet at 1 R_J with
> no irradiation (the default inlist_create_1.0_MJ_10.0_ME_2.0_RJ includes
> no irradiation, since it's really intended for creating a young, hot
> planet) has surface temperatures of order 100 K, so it's easy for a
> slightly lower guess for the central entropy to throw the surface far off
> the EOS tables.
>
> I'd echo Aaron's suggestion that you try a more inflated initial model.
> Then you could allow it to cool to 1 R_J (and possibly beyond) by just
> letting it evolve.
>
>
> chris
>
> On Mon, Jan 30, 2017 at 3:28 PM, Aaron Dotter <aaron.dotter at gmail.com>
> wrote:
>
>> Hi,
>>
>> It's a good idea to send your inlists along with your email describing
>> the problem.  This let's others try to reproduce your error.
>>
>> That said, my guess is that your are at or beyond the EOS limits.  Have
>> you tried intermediate values between 2R_J and 1 R_J?
>>
>> Aaron
>>
>>
>>
>> On Monday, January 30, 2017, Songhu Wang <songhuwang86 at gmail.com> wrote:
>>
>>> Hi all,
>>>
>>> These days, I try to conduct some planetary evolution work using MESA,
>>> although most of my previous work focus on observations.
>>> There is a developed demo case, named 'make_planets', in star/test_suite
>>> in released mesa directory (I use mesa-r8845).
>>>
>>> In this demo case, we need three steps to build and evolve a planet:
>>> 1. create an atmosphere envelop (inlist_create)
>>>
>>> 2. insert a core (inlist_core)
>>>
>>> 3. evolve (inlist_evolve)
>>>
>>> Now, I have a problem in the first step.
>>> In the demo case, they try to build a 2R_J planet (
>>> radius_in_cm_for_create_initial_model) with 1M_J (
>>> mass_in_gm_for_create_initial_model).
>>>
>>> I can run this demo smoothly, but when I try to use 1R_J as initial
>>> planet radius (radius_in_cm_for_create_initial_model), I found no
>>> matter what initial planet mass I choose, I can not run the code anymore.
>>>
>>> The reported error is attached.
>>> [image: Inline image 1]
>>> Can you give me some suggestions?
>>>
>>>
>>> Thank you,
>>> Songhu Wang
>>> -----------------------------------
>>> 51 Pegasi b Fellow in Yale
>>>
>>
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>
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