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

[Bill Paxton]

Hi Ale,

On Nov 2, 2010, at 4:35 PM, Alessandro Patruno wrote:

> 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...


The control you want is called 'zams_filename' which is set by default to 'zams_z2m2.data'.
The code tries to open the zams file first in the current directory and, if that fails, next
in mesa/data/star_data/zams_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 ??

Please send the saved model and the inlists so I can try to recreate the problem.

BTW: does the saved model evolve reasonably if you run it outside of the rlo setup?

> 
> Many thanks, I really appreciate your support !

You are very welcome!

Cheers,
Bill