A thin spherical shell has outward pressure force and inward gravitational force . Hydrostatic equilibrium requires
A uniform-density solar model gives , , and after integration from to zero,
Thus the appropriate orders of magnitude are – and . The uniform-density approximation underestimates the actual central pressure because the Sun is centrally concentrated. Radiation pressure is neglected in applying the ideal gas law.
A thin spherical shell has outward pressure force and inward gravitational force . Hydrostatic equilibrium requires
A uniform-density solar model gives , , and after integration from to zero,
Thus the appropriate orders of magnitude are – and . The uniform-density approximation underestimates the actual central pressure because the Sun is centrally concentrated. Radiation pressure is neglected in applying the ideal gas law.