[Mesa-users] Evolution of a 9M_sun ZAMS star up to to core collapse

amar at aries.res.in amar at aries.res.in
Mon Sep 27 17:21:32 UTC 2021 

Dear MESA team,

Please provide your valuable suggestion to get the output written properly for the explosion of 9 solar mass ZAMS progenitor.

I am waiting for any kind suggestion. Please also let me know if you require any further information.

With regards,
Amar
----- Original Message -----
From: amar at aries.res.in
To: mesa-users at lists.mesastar.org
Cc: amararyan941 at gmail.com, goldberg at physics.ucsb.edu, fxt44 at mac.com
Sent: Wed, 22 Sep 2021 12:04:01 +0530 (IST)
Subject: Re: [Mesa-users] Evolution of a 9M_sun ZAMS star up to to core collapse

Dear MESA team, 

MESA Version : 11701 
OS : UBUNTU 20.04 
Sorry for the long email, but it was necessary to explain what I tried. 

A few months back, I tried to touch the lower limit of progenitors that result in core-collapse supernovae (SNe). For this purpose, I took a 9.0 solar mass ZAMS progenitor and could evolve the model up to the onset of core-collapse. However, a few changes were made to the inlist files in the ~/mesa/star/test_suit/example_make_pre_ccsn directory. The most suspecting modification was changing mixing_length_alpha to 0.01 in inlist_to_si_burn. I read many literatures regarding mixing length and found a few commendable suggestions. One such literature (Joyce et al. 2018, [ https://doi.org/10.3847/1538-4357/aab200 | https://doi.org/10.3847/1538-4357/aab200 ] ) says that " In the same way that αMLT is not a physical constant, it is also not a computational one. Because it is a free parameter, the value of αMLT must be determined on an individual basis in each stellar evolution code, and its value as determined by different codes will reflect the prescriptive differences among those codes—even though the target features to be reproduced are identical ". Besides, the MLT is still not well understood and it is yet to be explored. Further, as suggested by Prof. Jared, at the end of the evolution we checked the position of our model on HR diagram and also discovered that there are a few stripped stars that have been observed near the position of our model star ( please see fig1.png ). This suggests that our model could be physical as such stripped stars have been observed in nature. 
Fig1. The position of our model on HR diagram at the last evolutionary stages (at Z=0.0185 close to Z_sun or Z_milkyWay). This figure is taken from a lecture and has made use of Shenar et al. 2020, A&A, 634, 79. 

Thus, given the evidences, we assume our model to be physical and tried to evolve the model just before the shock reached the stellar surface using the ~/mesa/star/test_suit/example_make_ccsn_IIp directory with an explosion energy of 0.5x10^51 ergs. Eventually, the evolution stops in the inlist_shock_part3 stage by displaying a message min_m >= max_m. Recently, I was following the conversation between Kai-an & Prof. Jared and found out that this situation arrived because the ready_for_edep.mod had supersonic velocities. Then, I changed those velocities to the order of d0 and this worked as a sovereign remedy. The model evolved throughout and produced the mesa.abn and mesa.hyd files, which were incorporated in STELLA to produce the light curves and velocity evolution. But the outputs were not thoroughly written in the mesa.lbol_lnuc.txt ( please see fig2.png ), although the velocities (using mesa.vel_feII ) are written properly ( fig3.png ). The following settings were used to produce STELLA files : 

save_stella_data_when_terminate = .true. 
save_stella_data_filename = 'mesa' 
stella_num_points = 50 ! lesser number of zones are required for stripped stars (also tried 60, 100) 
stella_nz_extra = 0 
stella_min_surf_logRho = -5 ! to remove the high velocity components, (also tried -100, but same result) 
stella_min_velocity = 0 
stella_skip_inner_dm = 0.1 
stella_skip_inner_v_limit = 5d+07 
stella_mdot_years_for_wind = 1 
stella_mdot_for_wind = 0.25 
stella_v_wind = 10 
stella_show_headers = .false. 

Fig2 : Terminal output and mesa.lbol_lnuc.txt file plot for luminosity light curve 


Fig. 3 : Velocity evolution. The blue triangle shows the observed FeII 5169A velocity calculated from the spectrum. 

Please suggest how to get the output written properly. I have devoted a large amount of time in solving this issue without any success. Any suggestion could be extremely helpful for me. 

With regards, 
Amar 


From: fxt44 at mac.com 
To: amararyan941 at gmail.com, amar at aries.res.in 
Cc: fxt44 at mac.com, mesa-users at lists.mesastar.org 
Sent: Friday, April 9, 2021 9:51:51 AM 
Subject: Re: [Mesa-users] Evolution of a 9M_sun ZAMS star up to to core collapse 

thanks amar. 
fxt 






On Apr 3, 2021, at 11:11 PM, Amar Aryan < [ mailto:amararyan941 at gmail.com | amararyan941 at gmail.com ] > wrote: 
Dear fxt, 

Here I attach the png plot almost at the end of the evolution (inlist_finish). 

<grid_H_046755.png> 


With best regards, 
Amar 

On Sun, Apr 4, 2021 at 8:24 AM Francis Timmes < [ mailto:fxt44 at mac.com | fxt44 at mac.com ] > wrote: 

BQ_BEGIN
hi amar, 

will you share a plot of the final mass fractions from this 9 msun run? 

fxt 






> On Apr 3, 2021, at 10:29 AM, Amar Aryan via Mesa-users < [ mailto:mesa-users at lists.mesastar.org | mesa-users at lists.mesastar.org ] > wrote: 
> 
> Dear Bill, 
> 
> Many thanks for your prompt reply. Here I wish to mention that a few months back, we were struggling to get going with a 12M_sun ZAMS star progenitor but with some changes, we could successfully model ( with excessive bits of help from Jared Goldberg ) the 12M_sun ZAMS star and further got successful STELLA calculations providing the light curves and velocity evolutions. 
> 
> With best regards, 
> Amar 
> 
> 
> From: [ mailto:paxton at kitp.ucsb.edu | paxton at kitp.ucsb.edu ] 
> To: [ mailto:amar at aries.res.in | amar at aries.res.in ] 
> Cc: [ mailto:mesa-users at lists.mesastar.org | mesa-users at lists.mesastar.org ] , [ mailto:Amararyan941 at gmail.com | Amararyan941 at gmail.com ] 
> Sent: Saturday, April 3, 2021 10:48:21 PM 
> Subject: Re: [Mesa-users] Evolution of a 9M_sun ZAMS star up to to core collapse 
> 
> just a quick comment: i’ve never been able to get 9M beyond the off-center Neon flash. Perhaps i’m just too impatient, but it takes longer than I’m willing to wait for the burning to make its way slowly to the center. with more massive models, the neon ignition is at the center so things go smoothly. you are welcome to try, but it might go easier if you can redefine your problem to 12M or more. 
> 
> cheers, 
> bill 
> 
> 
> On Apr 3, 2021, at 10:12 AM, Amar Aryan via Mesa-users < [ mailto:mesa-users at lists.mesastar.org | mesa-users at lists.mesastar.org ] > wrote: 
> 
> Dear MESA user team, 
> 
> I am trying to make a 9M_sun ZAMS model with Z=0.02 that explodes as a type IIb SN. Gladly, I could evolve the star up to the stage of Fe core infall, using the default star/test_suit/example_make_pre_ccsn with few modifications. Although I could evolve the model up to Fe core infall, I am not sure about a few parameters to be physical : 
> 
> Now here I briefly mention the changes in the inlist_files of example_make_pre_ccsn directory : 
> 
> a) In inlist_common, varcontrol_target = 1d-3, 
> mixing_length_alpha = 2.0 
> mixing_delta_coeff_for_highT = 2.5 
> f = 0.007 (Not sure if this is allowed!) 
> f0= 0.001 
> 
> b) In inlist_set_alpha_mlt, x_ctrl(21) = 2.5 
> x_ctrl(22) = 1.5 
> x_ctrl(23) = 0.5 
> 
> 1) In Inlist_to_zams, varcontrol_target = 1d-5 
> 
> 2) In inlist_to_zams, varcontrol_target = 1d-5 
> 
> 3) In inlist_remove, varcontrol_target = 1d-5, 
> mass_change = -1d-4 
> star_H_mass_min_limit = 0.013 
> 
> 4) In inlist_before_remove, ! varcontrol_target = 1d-2 (Not used) 
> Steps_to_take_before_terminate = 2 
> 
> 5) In inlist_to_si_burn, varcontrol_target = 5d-4, 
> mixing_length_alpha = 0.01 (seems to be too low but anything greater than 0.01 did not worked, setting this to 0 also failed!!) 
> 6) In inlist_to_lgT9.9, varcontrol_target = 5d-4 
> 
> Please provide your valuable suggestions regarding f, f0, mixing_lenth_alpha, and other major mistakes if any in the above parameters. 
> 
> With best regards, 
> Amar 
> 
> 
> 
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<grid_H_046755.png> 

BQ_END

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