[Mesa-users] Models failing to reach core collapse

Bill Paxton paxton at kitp.ucsb.edu
Sun Jan 27 20:41:04 EST 2019 

Hi Dan,

This may not be relevant to your particular project, but your comments about the 15.0 M failure to collapse made me curious.  So I just ran the example_make_pre_ccsn_test case for 15 M, Z = 0.02, Dutch wind scaling factor 1.0 (giving a final mass of 12.6), and it went to core collapse without problem (this is in a recent development version of mesa, 11422) .  Here’s the final terminal output:

stop because fe_core_infall > fe_core_infall_limit
    0.4650359313E+08    0.3000000000E+08

       2176  10.541897   3879.074 -99.000000 -99.000000  12.605994   7.570430   0.000000   0.000000   0.311644   0.404318   6.297116    724      5
  -0.718812  11.147967   2.869498 -99.000000  17.001497 -99.000000   5.035564   0.004356   0.000000   0.020059   0.319058   3.731929      5      0
 4.0913E+14  29.569784   5.047390 -99.000000   2.332494  -9.057282   3.172464   0.000000   0.000000   0.000000  2.766E-01  0.000E+00    varcontrol
                             center fe56        0.9879398679465048
                          fe_core_infall      465.0359312742229463
                               rel_E_err       -0.0007743502753213
                       log_rel_run_E_err       -2.2351024083554245


In my experience it is usually easier to start from something that works and make small step-by-step changes to get what you really want.  If you are interested in getting a 15 M case to core collapse with certain parameter settings, you might consider starting from this example and working from there.

Good luck,
Bill



> On Jan 27, 2019, at 3:59 PM, Dan Patnaude via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> 
> Hi Rob-
> 
> Thanks for pointing this out. There are two things to point out here, one related to the mesa marketplace, and another related to the inlists. 
> 
> 1: On the mesa marketplace (http://cococubed.asu.edu/mesa_market/inlists.html <http://cococubed.asu.edu/mesa_market/inlists.html>), the inlists from your paper linked here (http://cococubed.asu.edu/mesa_market/ewExternalFiles/Variations_rf.zip <http://cococubed.asu.edu/mesa_market/ewExternalFiles/Variations_rf.zip> , under the "Get" URL) vs those linked through the 
> dropbox https://www.dropbox.com/sh/yclyf0fv7az8eya/AAAUeaqJYLeBYb0-CXeZ82Kza?dl=0 <https://www.dropbox.com/sh/yclyf0fv7az8eya/AAAUeaqJYLeBYb0-CXeZ82Kza?dl=0> are not the same. The dropbox files are consistent with what are in your paper and what  you suggest. The "marketplace" inlists don't mention overshoot and don't set the Ledoux criteria to true. This probably needs to be fixed by the MESA folks.
> 
> 2: Even with using the appropriate inlists, Taylor and I are still unable to get the 15M core to collapse. I don't think this is related to "islands of explodability," as these are the exact same inlists I used in my 2017 paper, version 7624, where I was able to get a core to collapse just fine. 
> 
> So I guess the 1st question is, have you been able to reproduce some of your results using the latest stable release of MESA? Perhaps if you have the time, you can work with us to iron out the issues.
> 
> Thanks,
> Dan
> 
> 
> On Thu, Jan 17, 2019 at 4:44 AM Rob Farmer <r.j.farmer at uva.nl <mailto:r.j.farmer at uva.nl>> wrote:
> Hi,
> 
> I see you've removed overshoot from your models. I find that having even a little bit of overshoot usually helps mesa evolve a model more efficiently, as it smooths the composition boundaries. Also you've removed the use_Ledoux_criterion=.true. so your using the default use_Ledoux_criterion=.false. which means schwarzschild convection boundaries. Again i've found ledoux to make the evolution easier (but this depends on what physics you want to test, if you want to change it)
> 
> The other thing to do is work out what is happening inside the star that is causing problems. Kippenhan/abundance profile/mixing profile plots can help here to see how the burning/mixing is behaving and if it seems to get stuck somewhere particular (core burning? shell burning? which fuel?) which can help refine what you need to change to get the model working.
> 
> I'd also look at what is limiting the timetsep. This is given by the string in the last entry of the terminal output for a step (called dt_limit). That limit can then be compared to the names here http://mesa.sourceforge.net/controls_defaults.html#timestep_controls <http://mesa.sourceforge.net/controls_defaults.html#timestep_controls> and that will give you the timestep control that is currently limiting your evolution.
> 
> Rob
> 
> 
> On Thu, 17 Jan 2019 at 05:42, Jamie Tayar <jtayar at hawaii.edu <mailto:jtayar at hawaii.edu>> wrote:
> Hi Taylor,
> This isn't really my area of expertise, so I'll let someone else comment on the details of your models, but 15 solar masses is right around where the 'islands of explodability' start to show up (e.g. Figure 5 of https://arxiv.org/abs/1602.05956 <https://arxiv.org/abs/1602.05956> or Figure 8 of https://arxiv.org/pdf/1710.03243.pdf <https://arxiv.org/pdf/1710.03243.pdf>), and some fraction of models never reach the sort of compactness that indicates a successful collapse, so there's a possibility that what you're seeing is physics and not numerics.
> Apologies if you've already thought of that,
> Jamie
> 
> On Wed, Jan 16, 2019 at 6:25 PM Taylor Jacovich via Mesa-users <mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>> wrote:
> Hello all,
> 
> Have run into an issue with the current version of MESA where stars with a specific mass will never reach core-collapse (fe_core_infall > 10**3km/s stopping condition).  A full description of the issue and all the model data can be found here: https://gitlab.com/wind-loss-testing/readme <https://gitlab.com/wind-loss-testing/readme> .
> 
> The reader’s digest version is that stars with a certain mass (eg. 15.0Msun) will get stuck at a sub-Chandrasekhar mass iron core and happily coast for weeks at a time.  Meanwhile masses directly around the ones that fail to collapse (eg. 14.9Msun and 15.1Msun) will collapse without fail.  We are using Farmer’s inlists that were designed to help with explodability, and the only parameter we change between runs is the mass. 
> Any suggestions on new parameters to try or other options that may relieve the issue are much appreciated. Inlists are attached below, or you can clone from this directory https://gitlab.com/wind-loss-testing/windloss-template <https://gitlab.com/wind-loss-testing/windloss-template> to have an identical experience.
> 
> Thank you,
> 
> 
> Taylor Jacovich
> 
> 
> _______________________________________________
> mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
> https://lists.mesastar.org/mailman/listinfo/mesa-users <https://lists.mesastar.org/mailman/listinfo/mesa-users>
> 
> _______________________________________________
> mesa-users at lists.mesastar.org <mailto:mesa-users at lists.mesastar.org>
> https://lists.mesastar.org/mailman/listinfo/mesa-users <https://lists.mesastar.org/mailman/listinfo/mesa-users>
> 
> _______________________________________________
> mesa-users at lists.mesastar.org
> https://lists.mesastar.org/mailman/listinfo/mesa-users
> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20190127/b16d1403/attachment.html>

More information about the Mesa-users mailing list