Impact of a small orbital eccentricity (e ≈ 0.03) on the modeled GeV orbital light curves. The red dashed thick curve represents the circular-orbit best-fit solution. The solid curves in different colors show elliptical-orbit models with four representative arguments of periastron, ω = 0°, 90°, 180°, and 270°. The black circles show the Fermi-LAT data. All elliptical cases yield somewhat worse fits than the circular benchmark, indicating that even a small eccentricity introduces a noticeable but not decisive distortion of the orbital modulation profile.