mesa-users] Problem creating low Z stars and ZAMS models

[Alessandro P. <ale...@gm...>]

Hi everyone,

I was playing a bit with the test_suite
"low_z" and "create_zams" but I found two problems
I can't solve easily

1. How do I tell MESA to use a ZAMS model file that I created with
"create_zams" instead of the default ones ? I just created a Z=0.0001
ZAMS sequence (for Population II stars) and I'd like to use it now to load
initial stellar models...


2. I am creating a single star, a main sequence star of 0.9 Msun,
with Z=0.0001. So I use "low_z" in the test_suite.
My "inlist_low_z" has the lines:

&star_job
      mesa_data_dir = '../../../data' ! for eos and opacity tables
      create_pre_main_sequence_model = .true.
      save_model_number=635
      save_model_filename='0p9-z0001.dat'


I start with a pre-main sequence model
and then let the evolution go until the code tells
me "starting main sequence". This happens at the 635-th time step
(that's why I wrote save_model_number=635).
I save the model in the file (0p9-z0001.dat), and I load it in the
test_suite called "rlo" to do binary evolution.

The inlist_test_rlo file has these lines n the &star_job section:

&star_job

      mesa_data_dir = '../../../data' ! for eos and opacity tables
      log_columns_file = 'log_columns.list'

      load_saved_model=.true.
      saved_model_name='../low_z/0p9-z0001.dat'

      pgstar_flag = .true.


I place the donor at a very large orbital separation (something like 10^10
days)
to "simulate" a single star evolution before doing the real
binary evolution later.
However, the evolution is weird, the main sequence lasts for ~7.5 Gyr
(instead of the expected 12 Gyr)
and the evolution is very quick with the star becoming fully radiative
at some point...

Any idea what did I do wrong ??

Many thanks, I really appreciate your support !

Ale