[Mesa-users] Increased irradiation during planetary evolution

[Josiah Schwab]

Hello Marit,

Thank you for providing the inlists necessary to reproduce you work.

Ultimately, the source of your issue is that you are dramatically
changing the irradiation_flux over a single timestep.

As you say:
> the model receives an increase in flux from 6e4 erg/s to 6e8 erg/s
> over a timescale 1e5 yrs

MESA doesn't know anything about this timescale so it can be
timestepping along with timesteps of ~1d5 years.  (You can see this in
your plot).  Then WHAM! s% irradiation_flux suddenly increases by 10^4
in a single step.  MESA will not handle that gracefully.

You need to make sure that the model timestepping is such that the
increase in irradiation flux happens gradually.  One way to accomplish
that might be to limit the fractional change over a single step of the
"r" value that you're evolving.  For example, you could use
extras_check_model to force a retry (which will reduce the timestep).

Josiah