[Mesa-users] Unable to change temperature gradient when atomic diffusion is turned on

[Joey Mombarg]

Dear mesa-users,

I am trying to change the temperature gradient to the adiabatic one in the overshoot zone using the run_star_extras routine from Michielsen et al. 2019, where also atomic diffusion and radiative levitation are turned on. While mesa does indeed report that s% adjust_mlt_gradT_fraction(k) = 1 just before calling adjust_gradT_fraction (around line 668 in star/private/mlt_info.f90, r11701), it seems to be overwritten later in star/private/hydro_vars.f90, around line 565:

            if (.not. skip_mixing_info) then
               s% mixing_type(1:nz) = no_mixing
               s% adjust_mlt_gradT_fraction(1:nz) = -1
            end if

This condition seems to be fulfilled during the main-sequence evolution when atomic diffusion is turned on. I was wondering why adjust_mlt_gradT_fraction is changed to -1 here, and if there are any objections in removing this behaviour for this particular case? 

Kind regards,
Joey