[mesa-users] cool_brown_dwarf

[tahere parto]

Dear mesa users,

I'm trying to implement MESA to find a minimum mass for ZAMS
(the minimum mass for a star which can develop a hot core to be able
to burn hydrogen as the main source of energy and start main
sequence stage). as you recommended me before, I use
\star\test_suite\cool_brown_dwarf for this purpose.

When I run the code without any change, after a while it stops with this
termination code: max_age all result are okay .

Then I change the mass from 0.064 to 0.08 and run the code for each mass
and I noticed some problems.
for some masses the code encountered a convergence problem and stops with
this error:

hydro_newton_step failed to converge
stopping because of convergence problems dt < min_timestep_limit
terminated evolution: convergence problems

I change some conditions in controls and star_job like initial dt,
years_for_initial_dt, varcontrol_target ,max_age and I also change
mesh_delta_coeff=0.5 to mesh_delta_coeff=0.1.

&star_job

!set_initial_dt = .true.

!years_for_initial_dt = 1d-7


&controls

!varcontrol_target = 3d-5

mesh_delta_coeff = 0.1

!max_age = 10.1d9

Then convergence problem doesn't happen and The code stops with one of
these termination code depend on which mass I use. For some masses I
encountered ( Log_Q limit failed ) message and for some masses (max model
number failed) message.
Here are my questions:

Is it okay to change those conditions and the code stops running because of
reaching max model number failed?

How can I handle log_Q limit failed?

Thank you in advance,

Tahere
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20161115/2df4ad07/attachment.html>