[Mesa-users] shallow convection zone parameters

[Morgan Taylor]

Hi Anwesha,

My initial thought is to start with a lower zams mass.  The default starts
with a 3.1 ZAMS and spits out a 0.6 co wd.
Perhaps a lower mass will help you.
You can do this in the test suite by running all portions of the evolution,
from the zams and edit inlist_common's initial mass (maybe lower
metallicity too).
(you'll need to tell the inlist to use inlist_zams and
inlist_to_end_he_burn and use the rn1 executable).

I'm running the make_co_wd case with a 1.0 Msun zams on the side to check
this, but it will take some time to finish.
I can get back to you on the logP near the base of convection when it's
done.

Other options are to look at the helium white dwarf test suite case results
for logP near the surface, or try out wd_builder,
which uses ab-initio models that start at the wd cooling track, given a
composition file and initial mass.

Meanwhile, others may have a better solution than these though.

Morgan

On Sun, Dec 4, 2022 at 9:36 PM Anwesha Biswas via Mesa-users <
mesa-users at lists.mesastar.org> wrote:

> Hello,
>
>  I am trying to evolve a co wd using the test suite make_co_wd.
> the changes to the original inlist made by me:
> log_L_lower_limit = -2d0 (inlist_settle, need to get down to Teff<10,000K)
>
> added options in controls: (inlist_remove_envelope, inlist_settle,
> inlist_common)
> delta_lgTeff_limit = 0.001d0
> calculate_Brunt_N2 = .true.
> write_pulse_data_with_profile = .true.
> pulse_data_format = 'GYRE'
> MLT_option = 'ML2'
> mixing_length_parameter = 1.6d0
>
> For around temperature 10860K to 11400K, at the base of convection
> zone(checked by locating brunt_N2 going negative near surface)
> an logS of ~ 9 erg/Kg and logP of ~ 9 dyne/cm2 is needed. However the
> lowest I could get is logP(base of cvs) = 14.1dyne/cm2
>
> Is there any way to achieve the desired pressure and entropy at bottom of
> CVZ (tried varying mixing length parameter from 0.6 to 1.6 with not much
> effect)?
>
> Anwesha
>
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