[Mesa-users] Model terminating after main sequence?

Sat May 30 14:38:05 EDT 2020

Hi Francis,

Thanks for the reply. Using those controls definitely helps, though I was
still running into the same problem for at least a few of the tracks.
Interestingly enough, I tried turning off semiconvection, and everything
ran smoothly! I even got the behavior I'm trying to reproduce.

I'm an observer at heart (and very much a mesa novice), so these models
should be everything I need. Thanks again for the help.

Best,

Trevor Dorn-Wallenstein
University of Washington
Astronomy Department
he/him

On Thu, May 28, 2020 at 5:08 PM Francis Timmes <fxt44 at mac.com> wrote:

> hi trevor,
>
> varcontrol_target as a timestep controller is a bad idea because its not
> really a timestep controller.
> it is wiser to use limits on physical parameters to control the timestep.
> a solution that has been tested over a wide range of masses in 12115 and
> 12778 is
>
> ! temporal resolution
>      varcontrol_target= 5.0d-3
>
>
> ! time step resolution on temperature and density changes
>       delta_lgT_cntr_limit   = 0.001   ! default 0.01
>       delta_lgT_limit = 0.05d0         ! default 0.5
>
>       delta_lgRho_cntr_limit = 0.005   ! default 0.05
>       delta_lgRho_limit = 0.1          ! default 1.0
>
>
> as the snippet below has a recognizable piece of one of my inlists,
> i get to flog myself repeatedly and often. i invite bill to pile on
> about misuse of varcontrol_target.
>
> fxt
>
>
>
>
>
>
>
>
> > On May 18, 2020, at 3:27 PM, Francis Timmes <fxt44 at mac.com> wrote:
> >
> > hi trevor,
> >
> > i recognize the inlist from a mesa summer school ...
> >
> > ebraheem farag and i have been seeing exactly what you describe.
> > we've made some inlist adjustments and are running a grid under release
> r12778 as i write.
> > so far so good, but give us another day or two before replying more
> substantially.
> >
> > fxt
> >
> >
> >
> >
> >
> >
> >
> >
> >> On May 15, 2020, at 2:51 PM, Trevor Dorn-Wallenstein via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >>
> >> Hi There!
> >>
> >> I've been running a grid of massive (15-30 M_sun in 1 M_sun steps)
> Z=0.006 models. I'm running into an odd problem where above 17 or 18 M_sun,
> the star leaves the main sequence, does a Henyey hook, then the timestep
> abruptly drops to zero and the model terminates. Tweaking the time/spatial
> resolution might change the mass where this starts by +/-1 M_sun, and
> sometimes fixes it for one of the higher mass models, but nothing works for
> the whole grid. It also seems to be insensitive to the input physics. I'm
> running the models with macOS 10.15.2, MESA version 12778, MESA SDK version
> 20.3.1.
> >>
> >> I admit that in my quest to find an answer, I've thrown what is
> probably too many controls at this problem. I've attached an HR diagram,
> ZAMS model that I'm starting the 18 M_sun run from, and the inlist. Weirdly
> enough, for my most recent runs, the "successful" models have very low time
> resolution. The time/space resolution controls I'm using are:
> >>
> >>  ! Finer mesh
> >>    mesh_delta_coeff = 0.5 !0.75
> >>    mesh_delta_coeff_for_highT = 1.0
> >>    max_allowed_nz = 50000
> >>
> >>  ! some mesh settings to increase around sensitive areas
> >>    mesh_dlog_pp_dlogP_extra = 0.015
> >>    mesh_dlog_cno_dlogP_extra = 0.15
> >>    mesh_dlog_3alf_dlogP_extra = 0.15
> >>    mesh_dlog_burn_c_dlogP_extra = 0.15
> >>    mesh_dlog_burn_n_dlogP_extra = 0.15
> >>    mesh_dlog_burn_o_dlogP_extra = 0.15
> >>    mesh_dlog_burn_ne_dlogP_extra = 0.15
> >>    mesh_dlog_burn_na_dlogP_extra = 0.15
> >>    mesh_dlog_burn_mg_dlogP_extra = 0.15
> >>    mesh_dlog_cc_dlogP_extra = 0.15
> >>    mesh_dlog_co_dlogP_extra = 0.15
> >>    mesh_dlog_oo_dlogP_extra = 0.15
> >>
> >>  ! temporal resolution
> >>
> >>    varcontrol_target = 5d-5
> >>    min_timestep_limit = 1d-12 ! (seconds)
> >>    max_timestep_factor = 1.10d0 !1.15d0
> >>    min_timestep_factor = 0.05
> >>
> >>  ! resolve the depletion of each fuel
> >>    delta_lg_XH_cntr_limit = 0.05d0
> >>    delta_lg_XH_cntr_max   = 0.0d0
> >>    delta_lg_XH_cntr_min   = -6.0d0
> >>    !delta_lg_XH_cntr_hard_limit = 0.02d0 !turned off for most recent run
> >>
> >>    delta_lg_XHe_cntr_limit = 0.05d0
> >>    delta_lg_XHe_cntr_max   = -1.0d0
> >>    delta_lg_XHe_cntr_min   = -6.0d0
> >>    !delta_lg_XHe_cntr_hard_limit = 0.02d0
> >>
> >>    delta_lg_XC_cntr_limit = 0.05d0
> >>    delta_lg_XC_cntr_max   = -1.0d0
> >>    delta_lg_XC_cntr_min   = -6.0d0
> >>    !delta_lg_XC_cntr_hard_limit = 0.02d0
> >>
> >>  ! this is mainly to resolve properly when the star goes off the main
> sequence
> >>    delta_HR_limit = 0.0025d0
> >>    delta_lgL_He_limit = 0.1
> >>
> >> Thanks in advance for any help or guidance.
> >>
> >> Best,
> >>
> >> Trevor Dorn-Wallenstein
> >> University of Washington
> >> Astronomy Department
> >> he/him
> >>
> <18M_at_ZAMS.mod><inlist><example_hr.pdf>_______________________________________________
> >> mesa-users at lists.mesastar.org
> >> https://lists.mesastar.org/mailman/listinfo/mesa-users
> >>
> >
>
>
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