Properties of the Sun
for zero age Sun and for today’s Sun
These graphs were produced by Dr. Bob Field of Cal Poly
using analyses provided by Dr. Joyce Guzik, research scientist in the Applied
Physics Division of Los Alamos National Laboratory. The analyses were performed
with her solar evolution codes. Note that some curves are plotted on linear
scales and later replotted on log scales or other
scales to show details that are otherwise unclear because of the vast number of
orders of magnitude variation in some properties.
The four sections are
Sun properties vary with radius
Estimated radial gradients in solar
structure
Photon mean free path and equivalent mean
free path
Sun properties vary with radius
it would be nice to graph the difference between the two curves
energy production above radius 1E+10 increases with age because the temperature rise increases the fusion rate even though density is constant and hydrogen abundance decreases with age
Mean free paths increase as the Sun ages
Each luminosity curve is normalized to its maximum value
To my surprise the core does not expand as the interior heats up and the surface expands
It is remarkable how little mass shift there is as the Sun ages
Estimated radial gradients in solar structure
I have been crudely re-analyzing the LANL code numerical outputs for the current age Sun. I have taken differences in parameters at various radii to generate estimates of gradients of pressure, mass, luminosity, and temperature which I can compare to the presumed values in the equations of stellar structure (radiative version only). My hope was that the numbers would in fact be solutions to these equations and of course they are! The only exception is the temperature gradient in the convective zone where the radiative equation is not applicable. To see the match, examine the faint blue dashed line overlying the red curve in the pressure gradient chart. Similarly, the blue dashed line coincides with the radiative portion of the red temperature gradient curve – but deviates dramatically in the convective zone. But I can calculate an equivalent opacity to force the radiative equation to work where it does not apply. I can then calculate an equivalent mean free path that photons would need to have to avoid producing convection instability, a purely radiative solar interior. The equivalent mean free path smoothly skyrockets with radius in the convective zone.
