mesa-users] Successful compilation

[Bill Paxton]

On Dec 3, 2008, at 7:19 AM, Marcin @ astrophysics wrote:

> I've updated mesa to 834 revision and recompiled the whole source.  
> There have been no warnings and errors.
> At this moment I am successfully running mesa with different inlist  
> parameters. It's great!


Wonderful!

> Could you tell me what are the ranges for initial mass and initial  
> Z in mesa?

The ZAMS starting models are in the mesa/star/zams_models directory.   
The release only has the Z=0.02 models, but I have others I can  
include if you'd like them.   The pre-built models go from 0.08Msun  
to 80Msun.

You're not limited to using the pre-built models.   The file star/ 
test/inlist has the control parameters, and in there you'll find

    ! starting specifications

       initial_mass = 1
       initial_Z = 2d-2


Try changing those to what you want, and see if the system can create  
something that matches.

Those same controls are used when you want to start from pre-main- 
sequence rather than ZAMS.

To switch to pre-main-sequence starting models, edit the inlist file

    create_pre_main_sequence_model = .true.
       pre_main_sequence_rho_bar = 1d-4

The "rho_bar" parameter is the average density of the proto-star.   
The system will create a polytrope (n=1.5) for a starting model.

You can also make composition changes.  The simplest ways are to use  
the change_Y and change_Z controls.  Just set the flag to true and  
specify the desired value.

    !change_Y = .true.
       new_Y = 0.29

    !change_Z = .true.
       new_Z = 0.018

In addition to changing Y and Z, you can change the set of isotopes  
by changing the net.   The "Basic" net has h1, he3, he4, c12, n14,  
o16, ne20, and mg24 (mg24 is a place holder for all things heavy!).    
If you'd like more details on what happens to the n14, you can add  
o18 and n22 by doing this

    change_net = .true.
       new_net_num = 65 ! Basic + o18 + ne22

There are also options for including more details for pre-main- 
sequence burning (h2, li7, be7, b8), and alpha chains, etc.  See mesa/ 
net/public/net_def for more details.

Finally, there's an option to include a velocity variable rather than  
making the hydro-static assumption that all velocities are  
negligible.  When velocities are included, there's an acceleration  
term included in the momentum equation.  To add velocities,

    set_v_flag = .true.
       new_v_flag = .true.


That's probably enough to get you started!

Let me know how it goes.

Cheers,
Bill

p.s. you might have noticed that there's now a mesa/colors package  
that has the code for calculating theoretical color magnitudes using  
color magnitude data from Lejeune, Cuisinier, Buser (1998) A&AS 130,  
65-75.

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