[mesa-users] time step adjustments

[Abhisek Datta]

Hi,

The following lines are from mesa/star/public/star_defaults.dek regarding
time step adjustments.

            !lg_XH_cntr is log10(h1 mass fraction at center)
            ! small timesteps as the center hydrogen is exhausted
           * delta_lg_XH_cntr_min = -6 ! ignore changes in lg_XH_cntr if
value is less than this
            delta_lg_XH_cntr_max = -3 ! ignore changes in lg_XH_cntr if
value is more than this*
            delta_lg_XH_cntr_limit = 0.1
            delta_lg_XH_cntr_hard_limit = -1

Can someone please explain the two lines which are in BOLD.
What is meant by ignore? Does it mean the time-step adjustment doesn't take
into account changes in lg_XH_cntr when outside the
max and min limits? Or does it mean that the changes are taken to be 0,
thus being less than "delta_lg_XH_cntr_limit" so that the next timestep is
reduced?


Abhisek Datta
IIT Kharagpur
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