Microlensing Detection Budgets for Exomoons: Perturbation Scales and Mass-Ratio Thresholds

This paper computes a quantitative budget for one aspect of exomoon physics: the subject stated in the title, evaluated from stated assumptions with every number produced by the deposited calculation. Headline results are ganymede_q = 7.80e-05; ganymede_duration_hr = 4.2; earth_jupiter_duration_hr = 26.9; earth_saturn_duration_hr = 49.2. Gravitational microlensing detects planets by the brief brightening they imprint on a background star's light as an intervening system crosses the line of sight. A moon adds a second, much briefer perturbation, either as a separate spike near the planetary event or as a distortion of it, and because microlensing is sensitive to mass rather than light it can in principle reach moons around planets The results are compared with published Solar System values and with the constraints attached to reported exomoon candidates where those apply, and the conditions under which the computed budget would change are stated explicitly. Computed from stated assumptions, not measured.