[Mesa-users] Changing reaction rate issu in PPISN

Fri Jan 21 08:33:56 UTC 2022

Thanks Warrick,

I did try exactly that for a few models but it didn’t seem to change
anything so I just wanted to be sure I had the correct controls set.

I’ll experiment some more.

Cheers,

Jeremy

On Thu, Jan 20, 2022 at 22:30 Warrick Ball <W.H.Ball at bham.ac.uk> wrote:

> Hi Jeremy,
>
> I just searched `controls.defaults` in r12778 and found the following near
> the end of "mixing parameters" (just before "rotation controls"):
>
>      set_min_D_mix = .false.
>      mass_lower_limit_for_min_D_mix = 0d0
>      mass_upper_limit_for_min_D_mix = 1d99
>      min_D_mix = 1d3
>
>      set_min_D_mix_in_H_He = .false.
>      min_D_mix_in_H_He = 1d3
>
>      set_min_D_mix_below_Tmax = .false.
>      min_D_mix_below_Tmax = 1d3
>
>      min_center_Ye_for_min_D_mix = 0.47d0
>
> They're all present in r15140 so you can see the HTML version here:
>
>
> https://docs.mesastar.org/en/r15140/reference/controls.html#set-min-d-mix
>
> I think Mathieu's suggestions corresponds to
>
>      set_min_D_mix = .false.
>      min_D_mix = 1d-2
>
> Cheers,
> Warrick
>
>
> ___________
>
> Warrick Ball
> Postdoc, School of Physics and Astronomy
> University of Birmingham, Edgbaston, Birmingham B15 2TT
> W.H.Ball at bham.ac.uk
> +44 (0)121 414 4552
>
> On Fri, 21 Jan 2022, Jeremy Sakstein wrote:
>
> > Hi Mathieu,
> > "Regarding running PPISN at low-Z: I would look at how sharp the core
> edges are in these models. Once wind-mass loss becomes too small, the cores
> become sharper and it is hard for pulses to get through them (as I found in
> models with no-winds at
> > finite Z). If you really want low-Z model an idea could be add some
> small extra mixing (D_mix = 1d-2 for example) to smooth the edges a bit
> without messing up the stars too much. N.B: I have not tested this myself."
> >
> > Thanks for this, I was not aware this could be an issue and am
> interested in testing it. I looked for D_mix in controls_defalts but
> couldn't find a verbatim control with that name. What's the control I
> should be looking for?
> >
> > I am using MESA-r12778.
> >
> > Cheers,
> >
> > Jeremy
> >
> > On Thu, Jan 20, 2022 at 9:52 AM Mathieu Renzo via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >       Hi Vaishnav and Harshda,
> >
> >       I believe you want to set num_special_rate_factors=1 in your
> inlist.
> >
> >       The exact setup to reproduce Farmer et al. results is available on
> zenodo: https://zenodo.org/record/3346593
> >       and https://zenodo.org/record/3559859 (and I believe
> https://ui.adsabs.harvard.edu/abs/2022ApJ...924...39M/abstract
> successfully used these).
> >
> >       Regarding running PPISN at low-Z: I would look at how sharp the
> core edges are in these models. Once wind-mass loss becomes too small, the
> cores become sharper and it is hard for pulses to get through them (as I
> found in models with
> >       no-winds at finite Z). If you really want low-Z model an idea
> could be add some small extra mixing (D_mix = 1d-2 for example) to smooth
> the edges a bit without messing up the stars too much. N.B: I have not
> tested this myself.
> >
> >       Hope this helps!
> >       Mathieu
> >
> >       On 1/20/22 2:17 PM, Vaishnav Rao via Mesa-users wrote:
> >       Dear MESA users,
> >
> > We have been playing around with the PPISN test suite for the past year
> in an attempt to understand and reproduce the black hole mass gap. We were
> facing difficulties in incorporating custom reaction rates for the C12-O16
> reaction in
> > our test suite.
> >
> > We have been attempting to reproduce the plots of the effect of CO
> reaction rates on the final BH mass as in Farmer et al., 2019 and Farmer et
> al., 2020 . Using the reaction rates from the files of the latter, we tried
> to run a modified
> > test suite with recommended settings (which had already run for the
> default rates for us before). However, upon comparing the final BH masses
> for 0 sigma and -1 sigma rate tables, there was no major difference, even
> though there is an
> > expected difference of 8M in the final BH masses. Clearly the lines
> >
> > num_special_rate_factors=0
> > reaction_for_special_factor(1)='r_c12_ag_o16'
> > special_rate_factor(1)=1.0d0 ! Used for linear scaling of rates
> >
> > rate_tables_dir='rates/c12alpha/rate_tables-1s’
> >
> > which specify the path to the modified rate tables do not seem to be
> having any major effect on the simulations.
> >
> > Our simulations are for metallicities of 1d-3 (in accordance with Farmer
> et al., 2019). We chose this metallicity because our simulations for 1d-5 (
> as in Farmer et al., 2020) faced multiple convergence issues (mostly
> ‘hydro_failed’ or
> > too many retries). According to the other posts we saw on the MESA
> mailing list archives, many others too faced convergence issues of this
> sort for such low metallicities. We are not sure whether using the same
> rate tables for different
> > metallicities is correct.
> >
> > Our inlist, run_star_extras, and rate tables (zip file) have been
> attached for reference. Any advice on solving this issue would be
> appreciated.
> >
> > Software details:
> > MESA version: r12778
> > SDK version: March 25, 2020
> > OS: Cluster, 64-bit Linux
> >
> > Thanking you in advance,
> > Vaishnav V. Rao & Harshda Saxena
> > Department of Physics
> > Indian Institute of Technology Bombay
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> >
> >
> > --
> > Mathieu Renzo
> > Flatiron Research Fellow
> > Center for Computational Astrophysics
> > Columbia University
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> >
> https://urldefense.com/v3/__https://lists.mesastar.org/mailman/listinfo/mesa-users__;!!IBzWLUs!ABtxVxvf_FCkApSkViSy473uCSgoV0h6ZsUFt3-meFhtMdAI8BR-D0E9ouLqrlXpcfY$
> >
> >
> >
> > --
> > Jeremy Sakstein (He/Him/His)
> > Assistant Professor of Theoretical PhysicsDepartment of Physics &
> Astronomy
> > University of Hawaiʻi at Mānoa
> > Watanabe Hall
> > 2505 Correa Road
> > Honolulu, HI, 96822, USA
> > http://www.jeremysakstein.com
> >
> >

-- 
Jeremy Sakstein (He/Him/His)
Assistant Professor of Theoretical Physics
Department of Physics & Astronomy
University of Hawaiʻi at Mānoa
Watanabe Hall
2505 Correa Road
Honolulu, HI, 96822, USA
http://www.jeremysakstein.com
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