[amlhovsv] Core power

The core of the sun has power density 276.5 W/m^3, which is surprisingly low (but explainable because of the weakness of the weak nuclear force).  The density at the core of the sun is 150e3 kg/m^3 (150 times denser than water).  Divide them to get that the specific power at the core is 1.84 mW/kg.  Inverse is 542 kg/W.

Describe the physical models by which the above input numbers were computed, because of course we cannot go and sample the center of the sun.