Derivation of the Gravitational Constant and the Photogravitational Ratio from Single-Star Observables

This short report proposes a derivation of Newton's gravitational constant (G) from single-star observables: luminosity (L), mass (M), and surface gravitational acceleration (a). By defining the Photogravitational Ratio, ϕ = L / (M · a) we extract an expression for G using only photometric and dynamic surface measurements. This dimensionally consistent ratio (ϕ) may serve as a comparative astrophysical index and hints at an intrinsic photonic–gravitational coupling. Two example stars (the Sun and Sirius A) are used to validate the results. The derived values for G closely match the accepted constant. The model may inspire re-evaluation of gravitational inference from stellar photometry