Photogravitational Derivation of G and Stellar Ordering on the Φ Spectrum

This note introduces the photogravitational index (Φ) as a dimensionless parameter for classifying stellar structure by the balance of radiation and gravity. Defined Φ = L / (M × a) it enables comparison across stellar types. Using TIC catalog data, we computed Φ for 20 stars (see Table 1). A clear correlation between Φ and luminosity is shown in Figure 1. High Φ values reflect radiative dominance, while low Φ values indicate gravitational compression. This supports Φ as a continuous, physical classifier for stellar structural states. Update (Table 1 Correction): In the previous version, Φ values were calculated using surface gravity (a) values taken directly from the TIC catalog, which are provided in non-SI units (e.g., cm/s² or log g). This caused a scale difference from the definition given in the paper. In this updated version, a is recalculated from GM/R² in SI units (m/s²) for each star, ensuring consistency with the defined formula: Φ = L / (M × a) The corrected table replaces the original Table 1. All other text in the manuscript remains unchanged.