[Mesa-users] Questions about (step)Overshooting

[Matheus Bernini]

Hi Richard,

Indeed, at some points they are too squared (but the gray track it wasn't
made by me, it is one of the public avaliable GENEC tracks, which I
downloaded from Ekström's website). I used ~10000 mesh points,
mesh_delta_coeff = 1.0 and set varcontrol_target = 1.0d-4 .Is this enough
to have a converged state? Actually, is there a practical, or "standard
way" to know if my models are properly converged?

Thanks

Em sex, 28 de set de 2018 às 10:25, RICHARD H D TOWNSEND <
townsend at astro.wisc.edu> escreveu:

> Hi Matheus --
>
> Your tracks in the HR diagram look rather jagged, and it may be that your
> calculations aren't properly converged. Have you tried running with shorter
> timesteps and/or a finer spatial grid?
>
> cheers,
>
> Rich
>
> > On Sep 27, 2018, at 6:39 PM, Matheus Bernini via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >
> > Hello,
> >
> > I'm an undergraduate student and I'm studying evolution of massive stars
> using MESA.
> >
> > I was "playing around" with step overshooting initial values (
> overshoot_f0_...) for hydrogen helium and nonburn core/shell and I noticed
> that slightly changes on f0 (but always keeping f - f0 = 0.1) caused great
> changes on the post-MS phases [figure].
> >
> >
> >     overshoot_f0_above_burn_h_core = 0.035
> >     step_overshoot_f_above_burn_h_core = 0.135
> >
> > vs.
> >
> >     overshoot_f0_above_burn_h_core = 0.030
> >     step_overshoot_f_above_burn_h_core = 0.130
> >
> > *For completeness, there was also an exponential overshooting on all of
> the models of 0.001 on helium and hydrogen core/shell
> >
> > If I understood correctly, the f0 is the starting point for the
> overshoot inward the region (core or shell) because the mixing coefficient
> is 0 on the edge of the region, not allowing the computations to happen.
> So, if f0 is just a "trick" to allow the computation of the overshoot, why
> changing it a little causes important changes on the evolution?
> >
> > Thanks :)
> >
> > -----------------------------------------------------------------
> > Matheus Bernini Peron
> > Undergraduate student
> > Observatório do Valongo,
> > Universidade Federal do Rio de Janeiro
> > Ladeira do Pedro Antônio, 43 - Saúde
> > Rio de Janeiro - RJ - CEP 20080-090
> > Brasil
> > ___________________________________________________________
> > Evolution 32Msun, no rotation, Z_init = 0.014, Y_init = 0.266
> > red: 0.135 - 0.035
> > blue: 0.130 - 0.030
> > gray: GENEC (Ekstrom+2012)
> > <image.png>
> >
> <inlist_massive_defaults><inlist_32M0><run_star_extras.f>_______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> >
>
>
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