[Mesa-users] Nuclear binding energy released

[David Arnett]

Christian Ott and I have the details worked out in our unpublished preprint
that I previously attached. Using TYCHO we got a detectable signal (the
center of the sun is lighter per nucleon, since He^4 is lighter than 4
protons, and so has a slightly faster sound speed).  This should be redone
with MESA. I volunteer to advise. Any takers?

On Wed, Jan 30, 2019 at 1:08 PM Bill Paxton <paxton at kitp.ucsb.edu> wrote:

>
> On Jan 30, 2019, at 11:54 AM, David Arnett via Mesa-users <
> mesa-users at lists.mesastar.org> wrote:
>
> How much mass does MESA show the Sun losing during main sequence burning?
>
>
>
> i think there are 2 issues being discussed here: eps_nuc and mass loss.
>  this started as a discussion of eps_nuc, and Dave pointed out the related
> mass loss question.  I believe Frank suggested that eps_nuc might still be
> correct even if mass loss from nuclear reactions is not accounted for
> correctly (by default, mesa is using baryonic mass instead of gravitational
> mass).  and Dave is correctly pointing out (as he has before) that the
> difference between baryonic and gravitational mass should be enough to make
> a difference in precise asteroseismic measurements.
>
> btw: ever since dave 1st pointed this out to me (back long long ago),
> there has been an option in mesa/star for this
>
>          !### use_mass_corrections
>
>          ! Gravitational vs baryonic mass corrections.
>          ! If false, then no distinction between gravitational and
> baryonic mass.
>          ! If true, then gravitational mass is calculated using mass
> corrections.
>          ! Note: may need to wait for pre-ms model to converged before
> turning this on.
>
>       use_mass_corrections = .false.
>
> so anyone who is interested in this can give it a try.  i make no promises
> that mesa/star will actually work when this is turned on since it isn’t a
> commonly used option.  but if someone (Dave?) wants to run models and check
> the effects on asteroseismology, the implementation of gravitational mass
> is there waiting for someone to break it.  that shouldn’t be hard to do.
>
> -b
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>
>

-- 
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
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