[Mesa-users] problem with small time-steps

[Ebrahim Hassani]

Dear Mesa-users

I edited the run_star_extras.f90 file of the ~/mesa-r21.12.1/star/work star
to consider dark matter effects in stars (After copying the files of the
star to the Home directory in Ubuntu 20.04). The edited code is working
correctly for 1.0 and 3.0 M_Sun stars. But, when I want to run the code for
2.0 M_Sun, it takes so many steps (at least more than 40000) for the star
to reach the final stages of its evolution. In fact, when 2.0 M_Sun star
leaves the main-sequence, its time steps become very small (~ 1 year and
sometimes less than 1 year). And for this reason, it takes so many
time-steps for the 2.0 M_Sun star to reach the final stages of its
evolution.

May I ask what might be the possible reasons for this problem? And how can
I solve this problem? And also, why the same problem does not happen for
the 1.0 and 3.0 M_Sun stars?

The attached files are the codes that I used in my work.

Best regards
Ebrahim Hassani
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