[Mesa-users] Question about calculating electron densities for high mass stars

[Francis Timmes]

the charge neutrality equation 

n_{electrons,matter} = n_{electrons,fermi_integral} - n_{positrons,fermi_integral}

determines the electron and positron chemical potentials in their fermi integrals, 
hence all other thermodynamic quantities. here, each number density n is in 1/cm^3.

the helm table tabulates n_{electrons,fermi_integral} + n_{positrons,fermi_integral}
and its first and second derivatives with respect to temperature and density.

clearer?

fxt




> On May 6, 2020, at 1:36 PM, Jeremy Sakstein <sakstein at hawaii.edu> wrote:
> 
> Thanks Frank.
> 
> Just to clarify, exp(lnfree_e) is the number density of all electrons and positrons in ?
> 
> On Wed, May 6, 2020 at 4:34 PM Francis Timmes <fxt44 at mac.com> wrote:
> the straight sum of the electron and positron number densities, not per nucleon.
> 
> fxt
> 
> 
> 
> > On May 6, 2020, at 1:24 PM, Josiah Schwab via Mesa-users <mesa-users at lists.mesastar.org> wrote:
> > 
> > Final question: does lnfree_e include positrons too?
> >  
> > My memory was that when on HELM this is the combined number of e^- & e^+ per nucleon, but you should probably check that before relying on it.
> > 
> > Josiah
> > _______________________________________________
> > mesa-users at lists.mesastar.org
> > https://lists.mesastar.org/mailman/listinfo/mesa-users
> > 
>