[Mesa-users] Models failing to reach core collapse

[Dan Patnaude]

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), the inlists from your
paper linked here (
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 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> 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 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> 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 or Figure 8 of
>> 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> 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 .
>>>
>>> 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 to have an
>>> identical experience.
>>>
>>> Thank you,
>>>
>>>
>>> Taylor Jacovich
>>>
>>>
>>> _______________________________________________
>> mesa-users at lists.mesastar.org
>> https://lists.mesastar.org/mailman/listinfo/mesa-users
>>
>> _______________________________________________
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>
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