[Mesa-users] Problem with 20Msun star and z=0.005 : Fe-core is not producing ?

Wed Jun 13 23:37:51 EDT 2018

Hi Warrick and Elena,

Thanks for the mail. Here you can find more information about the problem
(all necessary files are attached). I hope these will be useful .....

1) We are using MESA version 10398 with export OMP_NUM_THREADS = 8.

2) We initially used inlist_zams to evolve a 20Msun, Z=0.005, Pre-Main
Sequence star until ZAMS and saved it as 20Msun.mod . Then using
inlist_project, 20Msun.mod  was loaded and the surface rotation, v=
200kms-1 was switched-on at ZAMS and allowed it to run. However, even after
13000 steps it did not reach the core-collapse and was stuck in the silicon
core phase. We did not terminate the process, but the time-step became down
to 10^-8 yrs and the Si_cntr (Silicon center mass fraction) had stayed
almost constant at 0.48 for more than 10000 steps.

3) We were trying to change some conditions to make it work and added the
following conditions. After adding these conditions, the Silicon burning
was completed in around 9000 steps, but after letting it run for more than
50000 steps there wasn't any core collapse (Fe_core_infall > 1000 kms-1).

use_eosPTEH_for_low_density = .false. ! default .true.

use_eosPTEH_for_high_Z = .false. ! default .true.

dX_nuc_drop_limit = 5d-2

dX_nuc_drop_limit_at_high_T = 5d-3

dX_nuc_drop_min_X_limit = 5d-2

dX_nuc_drop_max_A_limit = 52

We expect to get the Fe core  and a  collapse ? but did not get that in
this case. I hope, now the problem is more clearly described and look
forward to get an useful advice in this regard ....

Best regards
Rupak

On 11 June 2018 at 22:20, Elena Ambrosi <ele.ambr at gmail.com> wrote:

> Dear Rubak,
> I don't know if this can help, because what I am saying should depend on
> the MESA release you are using.
>
> I see from your inlist that you stated the inizial_z, but you did not load
> the files containing the ZAMS model with that metallicity.
>
> I mean that you should use the create_zams folder in the test suite, and
> then, after  having created a file.data with that metallicity, write in
> your inlist:
>
> initial_z = 'your metallicity'
> zams_filename = 'your_metallicity.data'
>
> I hope this can help!
>
> Cheers,
>
> Elena
>
>
> 2018-06-11 10:08 GMT+02:00 Warrick Ball via Mesa-users <
> mesa-users at lists.mesastar.org>:
>
>> Hi Rupak,
>>
>> I'm not an expert in this area so can't help directly but you're more
>> likely to get useful advice if you provide more information.  In
>> particular, you've said the run "doesn't seem to progress from there". What
>> does that mean?  What is the state of the stellar model when it stops
>> "progressing"?  Does MESA stop?  If so, with what message?  Or do the
>> timesteps decrease to small values?  How small?  What does the terminal
>> output say the limiting factor is?  Have you looked at any relevant
>> examples in the test_suite?
>>
>> At the very least, you should provide enough information to reproduce the
>> "problem", which you haven't.  First, you haven't told us what version of
>> MESA you're using.  Second, a quick glance at the inlist suggests it
>> requires the initial model `20msun.mod`, which doesn't seem to be attached.
>>
>> I don't mean for you to necessarily answer each one of these questions
>> but rather to serve as examples of the kinds of questions a stranger could
>> ask to try to help diagnose the "problem".  Currently, your message
>> basically says "this inlist doesn't do what I want/think it should, please
>> help". When I ask for help on a forum, my rule of thumb is to expect
>> readers to put in no more effort than is demonstrated by the content of my
>> message to that forum.
>>
>> Cheers,
>> Warrick
>>
>>
>>
>> On Mon, 11 Jun 2018, mesa-users at lists.mesastar.org wrote:
>>
>> Dear Mesa users,
>>>
>>> I am trying to run MESA with 20Msun, Vrot=200kms-1, and z=0.005 to
>>> Fe-core infall >1000kms-1, without including any mass-loss, or
>>> overshooting. However, the run goes up to Si-burning stage and doesn't seem
>>> to progress from there. The Mesa inlist file is given below. Can you
>>> please let me know why Fe-core is not producing ? Any suggestion, how to
>>> proceed .....
>>>
>>> This is my inlist
>>>
>>> &star_job
>>>
>>>
>>>
>>> !LOAD from ZAMS model
>>>
>>>
>>> load_saved_model = .true.
>>>
>>> saved_model_name = '20msun.mod'
>>>
>>>
>>> set_initial_age = .true.
>>>
>>> initial_age = 0 ! in years
>>>
>>>
>>> set_initial_model_number = .true.
>>>
>>> initial_model_number = 0
>>>
>>>
>>> set_initial_dt = .true.
>>>
>>> years_for_initial_dt = 10
>>>
>>>
>>>
>>> ! rotation
>>>
>>>
>>> change_rotation_flag = .true.
>>>
>>> new_rotation_flag = .true.
>>>
>>> new_surface_rotation_v = 200.0 ! km/sec
>>>
>>> set_surface_rotation_v = .true.
>>>
>>>
>>> change_v_flag = .true.
>>>
>>> new_v_flag = .true.
>>>
>>> center_ye_limit_for_v_flag = 0.45d0
>>>
>>>
>>> auto_extend_net = .true.
>>>
>>>
>>> / ! end of star_job namelist
>>>
>>> !*----------------------------------------------------------
>>> ------------------
>>>
>>>
>>> &controls
>>>
>>>
>>>
>>>       initial_mass = 20
>>>
>>>
>>> ! opacity
>>>
>>>
>>>      initial_z = 0.005d0
>>>
>>>      use_Type2_opacities= .true.
>>>
>>>      Zbase = 0.005d0
>>>
>>>
>>>
>>> fe_core_infall_limit = 1.0d8
>>>
>>>
>>>
>>> Best regards
>>> Rupak Roy
>>>
>>> --
>>> ******************************************************************
>>> * Rupak Roy
>>> * Post Doctoral Fellow
>>> * Inter-University Centre for Astronomy and Astrophysics
>>> * Pune - 411007, India
>>> * Mob: +91-7066564678
>>> * E-mail : rupak at iucaa.in ; rupakroy1980 at gmail.com
>>> *******************************************************************
>>>
>>>
>>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>
>>
>

-- 
******************************************************************
* Rupak Roy
* Post Doctoral Fellow
* Inter-University Centre for Astronomy and Astrophysics
* Pune - 411007, India
* Mob: +91-7066564678
* E-mail : rupak at iucaa.in <rupak.roy at astro.su.se> ; rupakroy1980 at gmail.com
*******************************************************************
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