[Mesa-users] Nuclear binding energy released

[David Arnett]

How much mass does MESA show the Sun losing during main sequence burning?

On Sun, Jan 27, 2019 at 12:26 PM Francis Timmes <fxt44 at mac.com> wrote:

> depends on how eps_nuc is defined, yes?
>
> somewhat surprisingly eps_nuc wasn't precisely defined in previous
> mesa instrument papers, but this will change soon enough.
>
> fxt
>
>
>
> > On Jan 25, 2019, at 11:52 AM, David Arnett via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >
> > That misses the mass defect, which is tiny except for H burning, but
> should be detectable with helioseismology.
> >
> > On Thu, Jan 24, 2019 at 9:26 PM Bill Paxton <paxton at kitp.ucsb.edu>
> wrote:
> > for energy from burning with nuclear reaction neutrinos subtracted, you
> could use cumulative_nuclear_heating
> >
> > where
> >            s% total_nuclear_heating = dt*dot_product(s% dm(1:nz), s%
> eps_nuc(1:nz))
> > and
> >            s% cumulative_nuclear_heating = &
> >                s% cumulative_nuclear_heating_old + s%
> total_nuclear_heating
> >
> > you can add cumulative_nuclear_heating to your history columns list.
> >
> >  -b
> >
> >
> >> On Jan 24, 2019, at 3:44 PM, Josiah Schwab via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
> >>
> >> Hi Shiv,
> >>
> >> I want to compute the nuclear binding energy released by burning over
> the whole simulation.
> >>
> >> In that case, you also might consider computing the binding energy at
> the first step, storing that value, calculating it at subsequent steps, and
> then taking the difference.
> >>
> >> Note that the mass fractions are in s% xa(i,k) and there is also a
> binding energy value on chem_isos, i.e. chem_isos% binding_energy(ci).
> >>
> >> The bookkeeping might be complicated if your models have mass loss
> though.
> >>
> >> Hope that helps,
> >> Josiah
>
>

-- 
David Arnett
Regents Professor
Steward Observatory
University of Arizona

Facts are stubborn, but statistics are more pliable.  Mark Twain
Facts do not cease to exist because they are ignored.  Aldous Huxley
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20190130/cd0720c0/attachment.html>