[Mesa-users] Changing reaction rate issu in PPISN

Fri Jan 21 08:35:21 UTC 2022

D'oh!  Mathieu's suggestion would be

     set_min_D_mix = .true.    ! oops
     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, mesa-users at lists.mesastar.org 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
>> 
>> 
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