[Mesa-users] Evolution of pop III stars up to core-collapse with rotation

[Ramandeep Gill]

Hi Rob,

Thanks for writing back. Let me first answer your questions and then I
can provide some more details.

The model fails during Carbon ignition in the core. For your reference
I've attached two screenshots of the output just before the code
crashes. Fig.1 shows the Carbon fraction with C_cntr = 0.000131 and
this the lowest I've obtained with the current setup. The figure also
shows the current time step which is very small. The code crashes very
soon after this and that's shown in Fig. 2, just to give you some idea
of the error messages before it crashes. The time step is being
determined by max_increase, and I don't really know what that means.

I'll have to look into how to produce a Kippenhahn diagram. A quick
search on google revealed that many have written python scripts to do
just that. So, I might adopt one of them.

Finally, I looked at the MESA instrument paper II, which presents the
evolution of a 40 M_sun star with rotation for a low Z = 1e-5. I was
able to get the inlist for this paper from MESA marketplace. This
seemed like a perfect example for my case. I tried it with the most
recent version of MESA, and after fixing a few flags that have been
changed in the recent version, I was able to run it. However, it
crashed very quickly while core H ignition. Perhaps there's a way to
run this example with the latest version. Or I can try to install the
same version, if it's still available, that was used for that paper
and then run it.

Thanks,
Ramandeep

NB: In my original message I attached inlist_CC but it's missing some
flags that initialize the rotation. It's not the inlist that was used
to produce the attached HR diagram. So, I'm attaching the proper
inlist here. Sorry for the confusion.


On Wed, Mar 31, 2021 at 1:20 AM Rob Farmer <robert.j.farmer37 at gmail.com> wrote:
>
> Hi,
>
> The envelopes of massive stars are difficult things to get right. I would not worry (for now) so much about the envelope, instead worry about what the star is doing internally. How close to core collapse did your model get? Has it ignited carbon or later fuels? Try looking at a kippenhan diagram. If you look over the recent timesteps before the model crashes, what is limiting the timestep?
>
> Rob
>
>
>
> On Tue, 30 Mar 2021 at 22:13, Ramandeep Gill via Mesa-users <mesa-users at lists.mesastar.org> wrote:
>>
>> Hello MESA experts,
>>
>> I'm trying to obtain the pre-core-collapse structure of massive pop
>> III stars to study the launching and propagation of GRB jets in these
>> stars. In the end, I'm looking to obtain the density and angular
>> momentum radial profile of the star.
>>
>> To this end, I've tried a few inlists, starting from the bare minimum
>> one used for introductory MESA tutorials as well as more advanced ones
>> from the MESA test suite and any that I could find online. The end
>> result in all is that after core He depletion, the code crashes most
>> of the time or, if I manage to somehow stabilize it, settles onto a
>> spurious solution with a lot of wild oscillations.
>>
>> I attach an HR diagram from one of the runs for which I used the
>> inlist from the 'make_pre_ccsn_IIp' test suite example. The evolution
>> up to H core depletion, He core depletion, and that beyond He core
>> depletion is color coded. You can see that the last part of the
>> evolution results in spurious oscillations, after which the code many
>> times crashes or keeps chugging along at smaller and smaller time
>> steps.
>>
>> To reproduce these results, I'm attaching two inlists. One produces
>> the evolution up to ZAMS and the second is designed to take it from
>> there up to the core collapse (CC) stage. I'm using version r15140 of
>> MESA.
>>
>> At this point, I can use some help from MESA experts. What I'm looking
>> for is help in creating a basic inlist without any advanced effects
>> that can evolve the star to the core collapse stage. Advanced effects
>> can come later once I have a working solution for massive pop III
>> stars.
>>
>> I was hoping to reproduce the results of Yoon, Dierks, & Langer (2012)
>> shown in their Fig. 1 & 2. They show the evolution only up to He core
>> depletion. In my case, I need to go beyond this to the core collapse
>> stage with and without rotation.
>>
>> I'll really appreciate any help that you can offer. Please let me know
>> if you need any further info from me and forgive me if I haven't been
>> so clear in describing the problem.
>>
>> Thanks,
>> Ramandeep
>> --
>> Ramandeep Gill
>> Postdoctoral Fellow
>> George Washington University
>> The Open University of Israel
>> http://www.ramandeepgill.com
>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>


-- 
Ramandeep Gill
Postdoctoral Fellow
George Washington University
The Open University of Israel
http://www.ramandeepgill.com
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