Gravitational Microlensing: Light Curve Simulator (2D)

When an unseen foreground star drifts almost directly between Earth and a distant background star, its gravity briefly bends and focuses that star's light, splitting one image into two and brightening the whole system for days to weeks before fading back to normal. This 2D companion renders the same alignment as seen looking straight down the line of sight — the lens star sweeping past the source, its two lensed images straddling the Einstein ring — while plotting the exact Paczyński light curve the event produces, driven by the same impact parameter, Einstein crossing time and finite source size that astronomers fit to real microlensing surveys like OGLE and MOA.