A parameter-free model for temperature and pressure profiles in luminous, stable stars.

The historic, classical thermodynamic model of star interiors neglects luminosity (L), and consequently predicts ultrahigh central solar temperatures (T - 15 x 106 K). Modern models yield similar T profiles mostly because local thermal equilibrium and multiple free parameters are used. Instead, long-term stability of stars signifies disequilibrium where energy generated equals energy emitted. We assume that heat is generated in a shell defining the core and use Fourier's model, which describes diffusion of heat, including via radiation. to predict the T profile. Under steadystate, power L transmitted through each shell is constant above the zone of energy generation. Hence, L is independent of spherical radius (s), so the Stefan-Boltzmann law dictates T(s), and material properties are irrelevant. Temperature is constant in the core and proportional to Dtr-1/2 above. A point source core sets the upper limit on T(s). giving Taverage = (6/5) 1 451 r| ace• Core size or convecting regions little affect our results. We also construct a parameter-free model for interior pressure (P) and density (p) by inserting our T(s) formula into an ideal gas law (P/poLT) while using the equation for hydrostatic gravitational compression. We find P oc s-·1, p (X s-.5~, and paverage =6x p,uN-ace· Another result, Ln< mass·3·3, agrees with accepted empirical rules for main sequence stars, and validates our model. The total solar mass already "burned" suggests that fusion occurs near L„4400 where P - 0.5 x 1012 Pa, in agreement with H-bomb pressure estimates. Implications are discussed. [ABSTRACT FROM AUTHOR]