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

Wed Apr 7 12:22:21 UTC 2021

Hi,
Thanks, if you look at the kippenhan you see you actually start having
problems right after core h burning (and before c burning) note how the
edges of convection zones above the he shell are almost flat and constant.
That is a sign that the timestep has shrunk to a very small value at this
point. So have a look around model 1700 at what is limiting the timestep.

Looking at inlist_CC, the first thing to try is simplify it a bit, turn off
rotation, v_flag (hydro), D_omega, D_smooth. Does the model work? If so,
start turning them back on one at a time, when does it stop working?

I see you are not using type2_opacities i would suggest you do so, if you
are going beyond H burning you'll need to take into account the C/O
produced in the star.

>Many Z=0 works use
the Kudritzki model which is not one of the options in MESA and so I
couldn't use it. Perhaps there's another way to implement it.

MESA has hooks to alter the physics used, including wind mass loss. See
star/other/other_winds.f90 for details.

Rob

On Tue, 6 Apr 2021 at 01:14, Ramandeep Gill <rsgill.rg at gmail.com> wrote:

> Hi Rob,
>
> Thanks for your input on how to make the Kippenhahn diagrams in MESA.
> It was very helpful.
>
> I'm attaching below the results for the 60 M_sun model that was run
> using v15140. All files are labeled with the MESA version used. To
> remind you, this model crashes during core Carbon burn due to the
> timestep becoming too small. The attached figures may provide more
> insight into what might be going on.
>
> I also took the time over the last few days to experiment with other
> published inlists to see if they can be applied to my problem. I found
> one prepared by Matteo Cantiello for the paper Perna, Lazzati,
> Cantiello, 2018, ApJ, 859, 48. In that work, they evolve massive [40
> M_sun] stars with Z = 1e-5 from zams to iron core formation using
> MESA_v9793. First I tried the same inlist with the current MESA
> version, it didn't work due to several changes to the code. I was able
> to install v9793 successfully which I then used to reproduce Matteo's
> results from that paper. In the next step, I tried to lower the
> metallicity. I was able to get a solution for Z = 5e-7 until the
> formation of the Iron core, which I also attach [notice the different
> version v9793 in the attached figs].
>
> The problem here was that with the adopted mass-loss prescription due
> to radiative winds [Dutch with scaling factor 0.8], the star loses too
> much mass [from 60 M to 21 M] even with such low Z. Other works that
> evolve Z=0 stars find only minimal mass loss due to rotation. Lowering
> the Dutch scaling factor or turning it off completely crashes in MESA.
>
> If we can find a way to avoid very small time steps then some progress
> can be made. Let me know your thoughts on this. Another point that's
> worth considering is the mass loss prescription. Many Z=0 works use
> the Kudritzki model which is not one of the options in MESA and so I
> couldn't use it. Perhaps there's another way to implement it.
>
> Best,
> Ramandeep
>
> On Thu, Apr 1, 2021 at 12:53 AM Rob Farmer <robert.j.farmer37 at gmail.com>
> wrote:
> >
> > Hi,
> > There are python codes available for making kippenhans, but for now the
> simplest is to let mesa make them for you.
> >
> > Add:
> > mixing_regions 40
> > burning_regions 40
> > to your history_columns file
> >
> > and add:
> > kipp_win_flag=.true.
> > in your pgstar inlist
> >
> > Rob
> >
> >
> >
> > On Thu, 1 Apr 2021 at 01:13, Ramandeep Gill <rsgill.rg at gmail.com> wrote:
> >>
> >> 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
>
>
>
> --
> Ramandeep Gill
> Postdoctoral Fellow
> George Washington University
> The Open University of Israel
> http://www.ramandeepgill.com
>
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