mesa-users] Successful compilation

Marcin @ astrophysics astrophysics at
Wed Dec 3 14:43:24 EST 2008

Hi Bill,

Bill Paxton wrote:
> 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.
I like crossing borders :-P so...
I read mesa description at sourceforge and tried to run a model even of 
0.05Msun. Mesa successfully produced outcomes. May I rely on them?
However masses over 80 are really not welcome;-) Is it possible to 
expand mass boundaries? Let's say lower than 0.03Msun and higher than 
about 120Msun.

Yes, I would appreciate for other Z models. How many of them there are?

> 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.
So, could I change to any initial_Z (making sense of course) value I'd like?
Could you explain to me what is the difference between mentioned the 
only Z=0.02 models and different initial_Z values?

> 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 may be sure I'll try and test it. I'm very curious where would it go to.

> 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
It is really great. Are those values applicable to even main and 
pre-main sequence models? And again how does it imply to "one Z" and 

> 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.
Is it possible to use that burning to not pre-main sequence starts but 
to very low mass stars (Msun < 0.08)? I ask about Deuterium burning for 
stars not allowed to start Hydrogen burning.

> 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.
Oh yes, I've noticed! Thank you for that. How could I quickly add colors 
to the output (let's say B-V and U-B only) without heavy code digging 
for me at this moment?

Waiting for your reply, regards.


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