[Mesa-users] Formicola 2004 reaction rate

Meisel, Zach meisel at ohio.edu
Sun Oct 15 19:19:14 EDT 2017


Greetings Earl,

One of the best online references I can think of for this would be Hendrik Schatz’s nuclear astrophysics lecture notes. For the s-factor, this lecture should be useful: https://people.nscl.msu.edu/~schatz/PHY983_13/Lectures/rates_direct.pdf

-Zach

----
Zach Meisel
Asst. Prof. of Physics & Astronomy
Ohio University
Email: meisel at ohio.edu
Web: http://inpp.ohiou.edu/~meisel

From: Earl Bellinger<mailto:bellinger at mps.mpg.de>
Sent: Sunday, October 15, 2017 9:32 AM
To: Francis Timmes<mailto:fxt44 at mac.com>
Cc: mesa-users<mailto:mesa-users at lists.mesastar.org>
Subject: Re: [Mesa-users] Formicola 2004 reaction rate

Thanks Josiah and Francis for your useful replies. I've run through
the inlists and now can get all that to work.

I am still running into some difficulties however putting this into
practice in the context of the Formicola result. The update to this
rate comes in the form of the astrophysical s-factor. In other
evolution codes (e.g. YREC) it is possible to alter s-factors
individually. In an earlier mesa-users thread [1] however, Rob Farmer
explains that the s-factors cannot be altered directly in MESA;
instead, new reaction rates must be computed with the new s-factor. Is
that still the case? If so, does anyone have any advice as to how I
can calculate the rates manually with this different s-factor, so that
I may then insert them using the procedures described above?

Thanks again for any assistance.

[1] https://lists.mesastar.org/pipermail/mesa-users/2016-September/007051.html

Best regards,
Earl Bellinger

---
earlbellinger.github.io
Earl Bellinger, Ph.D. Candidate
SAGE Group, Max Planck Institute for Solar System Research
Department of Astronomy, Yale University


On Fri, Sep 29, 2017 at 7:56 AM, Francis Timmes <fxt44 at mac.com> wrote:
>
> hi earl,
>
> 1) unzip the attached rate_tables.zip file.
>
> 2) place the "rate_tables" folder in your mesa work directory.
>
> 3) inspect the contents of "rate_tables" :
>
>    "rate_list.txt" holds the (rate name, rate file) pair for strong and e&m rates.
>    in this example, it is set to use (r_c12_ag_o16, new_c12_ag_adopted.txt) pair,
>    so the c12(a,g) will be replaced by whatever is in "new_c12_ag_adopted.txt".
>
>    "weak_rate_list.txt" holds the (rate name, rate file) pair for weak reactions.
>    in this example, it is empty.
>
>    "new_c12_ag_adopted.txt" holds the (T8,rate) pairs to be interpolated and tabularized.
>    in this example, its a rendition of the new deboer et al 2017 c12(a,g) rate.
>
> 4) in the &star_job part of your inlist activate the custom rate with
>
> ! set any specific reaction rates
>        rate_tables_dir  = './rate_tables'
>
>
> hopefully (a) i haven't forgotten anything and (b) you can morph this into whatever rate(s) one wants.
>
> fxt
>
>
>
>
>
> > On Sep 28, 2017, at 11:06 AM, Josiah Schwab via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> >
> > Hi Earl,
> >
> > Sorry for the extremely brief reply.  (Maybe more later.)
> >
> >> As far as I understand it, the default nuclear reaction rates in MESA
> >> are the NACRE rates from Angulo et al. 1999 [1].
> >>
> >> In 2004, Formicola et al. [2] provided an update to the 14 N(p, γ) 15
> >> O reaction.
> >>
> >> Is this rate in MESA at present, perhaps with a hook to toggle it?
> >
> > No.  But MESA has JINA reaclib v2.2, where the default is
> >
> >  https://groups.nscl.msu.edu/jina/reaclib/db/n14(p,g)o15/im05/
> >
> > from G. Imbriani et al. (2005).
> >
> > I would guess those are quite similar since Imbriani was 2nd author of
> > Formicola, but I don't know.
> >
> >> Some grepping around indicates that the answer is 'probably not,' and
> >> so short of that, has anyone implemented it already for their own use
> >> and would be kind enough to share it?
> >>
> >> If not, I can implement it myself. I have a rough idea how to do it,
> >> although having never waded here before, suggestions for how to do it
> >> would also be appreciated :-)
> >
> > Take a look at the test_case custom rates for an example.
> >
> > Josiah
>
>
>

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