A New Method to Estimate the Masses of Wolf–Rayet Stars from Light and Surface Gravity

.This work introduces a fully observational method for determining the masses of Wolf–Rayet stars using the photogravitational parameter Φ ≡ L / (Mg). Unlike theoretical evolutionary models, this approach relies only on surface observables: luminosity, radius, and spectroscopic gravity. Calibrated on 12 WR+O binaries with known dynamical masses (∼9.2% RMS accuracy), the method is applied to 10 isolated WR stars. The results reproduce the well-known 35–54% discrepancy between evolutionary and empirical masses, with a median deviation of 42.5%. The paper presents a theoretical framework including a GR correction (Φ_GR), a closure metric (δ_GR), and falsifiable predictions in the Φ–β plane. This provides a model-independent explanation for the WR mass discrepancy and a practical path to mass estimates across the Galactic WR population.