[mesa-users] [MESA]: Question Astrophysical Factor

Robert Farmer rjfarmer at asu.edu
Mon Oct 31 14:18:55 EDT 2016


Hi
Please keep replies on the mesa users list, others may be able to help and
may be helped by any response.

>I've created the rate_tables directory and put the files there as you said
but the code seems to ignore my tables.

Did you alter your star_job inlist to point to the rates folder? I would
need to see your inlists, folder structure and rates files to see whats
gone wrong.

>1) If I do what you said for an existing reaction, like rpp_to_he3, the
code is supposed to ignore the default tables and use mine right? Or it
adds a new reaction with my tables?

It should use yours, if its been set up correctly

>2) On the table files (txt), what are the units of the "Rates" column?

Reactions per second

Rob

On Sun, Oct 30, 2016 at 10:59 AM, Gonçalo Andrade <gnmandrade at hotmail.com>
wrote:

> Hi Rob
>
>
>
> Thank you for your help. It took me a long time to produce properly the
> rate tables from the s-factor so I could only try your method a few weeks
> ago.
>
>
>
> I've created the rate_tables directory and put the files there as you said
> but the code seems to ignore my tables. I even tried to put really big
> numbers just to check if it was using the tables and the result was no
> different from what I had before.
>
> Is there any step missing? I always do "./clean && ./mk && ./rn" when
> running the code.
>
>
> Two more questions:
>
> 1) If I do what you said for an existing reaction, like rpp_to_he3, the
> code is supposed to ignore the default tables and use mine right? Or it
> adds a new reaction with my tables?
>
>
> 2) On the table files (txt), what are the units of the "Rates" column?
>
>
> Thanks a lot for your help.
>
>
> Gonçalo Andrade
>
>
>
>
> ------------------------------
> *De:* Robert Farmer <rjfarmer at asu.edu>
> *Enviado:* 16 de setembro de 2016 00:59
> *Para:* Gonçalo Andrade
> *Cc:* mesa-users at lists.sourceforge.net
> *Assunto:* Re: [mesa-users] [MESA]: Question Astrophysical Factor
>
> Hi
> You cant change the s-factor directly, however you can give mesa a file
> with a customized set of nuclear reaction rates where you have changed the
> s-factor yourself.
>
> What you need to do (and example inlists and rate files can be found here
> http://mesastar.org/results/properties-of-carbon-oxygen-whit
> e-dwarfs-from-monte-carlo-stellar-models) follows:
>
>
> Add this to the star_job section of your inlists
>
> rate_tables_dir = './rate_tables'
>
> Then make a folder rate_tables in your mesa work directory. Inside that
> folder make a file rates_list.txt file with the following line:
>
> r_h1_pg_h2     'r_h1_pg_h2.txt'
>
> This says we want to alter the reaction h1+h1 -> h2 by looking for a file
> called r_h1_pg_h2.txt where we will specify the rate as a function of
> temperature
>
> Then make a file called r_h1_pg_h2.txt in (rate_tables), where the first
> two lines are:
> #  r_h1_pg_h2 low rate:
> # T8            RATE
>
> Then you need to add a line with the number of rate points you have. Then
> give the temperature in units of 10**8 K and a rate with one rate per line.
> An example file might look like this though you will want many more rate
> points than this:
>
> #  r_h1_pg_h2 low rate:
> # T8            RATE
> 5
> 0.01    0.0
> 0.5      1.0
> 1.0      2.0
> 10.5    3.0
> 100.0 10.0
>
> Then run mesa and it should be using your new nuclear rate.
>
> Rob
>
>
>
> On Thu, Sep 15, 2016 at 4:25 PM, Gonçalo Andrade <gnmandrade at hotmail.com>
> wrote:
>
>> Dear Sir or Madam,
>>
>>
>>
>> I'm a MSc student and I'm doing my master thesis on asteroseismology of
>> red giant stars. I'm using MESA to do models of these stars.
>>
>>
>> I found this email on the MESA community website and I decided to try it
>> as a last resource.
>>
>>
>> The thing I need to do now in my project is to change the Astrophysical
>> Factor (S-Factor) from the pp nuclear reaction to try to find out what
>> changes does it have in the star and if these can be measured using
>> seismology. The problem is I've been been searching online for some weeks
>> and I can't find out how to change this factor. I've tried several things,
>> the closest to what I wanted, I think, was to change the value on the file
>> $MESA_DIR/rates/private/ratelib.f90 , but after that change the code no
>> longer compiles...
>>
>>
>> I a few words, I just need to change the S-Factor of the pp reaction.
>>
>>
>>
>> I thank you in advance and hope I'm not being inconvenient.
>>
>>
>> Yours faithfully,
>>
>> Gonçalo Andrade
>>
>>
>>
>> ------------------------------------------------------------
>> ------------------
>>
>> _______________________________________________
>> mesa-users mailing list
>> mesa-users at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/mesa-users
>>
>>
>
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