Astronomy

A planet's fingerprint in a lensing event

Move a background star behind a foreground lens. Add a planet and compare the magnification with the familiar single-lens light curve.

By Mykhailo Makarov

Actual application image

The model and its limits

Point-source geometric optics, the source at 8 kpc, the lens distance and transverse speed adjustable (the Einstein time follows). Binary-lens images are solved numerically; finite-source smoothing, parallax and orbital motion are omitted. Caustic peaks can be very sharp. Image separations are greatly magnified.

Equations used in the module

Equations
A(u) = (u²+2)/(u√(u²+4)); y = x − Σ m_i (x−x_i)/|x−x_i|²; A_i = 1/|det J_i|.

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