This is how we find worlds around other stars. Watch a planet cross its star and dim it by a fraction of a percent — the signal Kepler and TESS hunt for.
Exoplanet TransitLive
the transit method · light curves
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As a planet crosses its star, it blocks a tiny fraction of the light — a dip of depth (Rp/Rs)². This is how Kepler and TESS have found thousands of exoplanets. Impact parameter sets how centrally the planet crosses, changing the transit shape and duration. Drag the planet across the star to set its phase, or up and down to set the impact parameter — the light curve updates live.
Reading this result: The dip depth is almost exactly (Rp/Rs)², so measuring how much light is blocked directly gives the planet's size relative to its star. The width of the dip is the transit duration, which — combined with how often it repeats — follows from the planet's orbital period and speed across the disk.
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How it works
The transit method detects a planet by the periodic dip in its star's brightness as the planet passes in front. The depth equals (Rp/Rs)² — the ratio of the planet and star areas — and the impact parameter sets how centrally it crosses, shaping the light curve. This simulates the geometric overlap in real time.
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The math, the assumptions, real-world uses, or a code translation — explained for this exact simulation.
Is this exoplanet transit light curve tool really free?▾
Yes. Exoplanet Transit runs entirely in your browser using your device's own compute, so local use is free forever. You only pay Compute Tokens if you scale a job to the cloud.
Do I need to install anything?▾
No. Everything runs client-side in a modern browser — no downloads, no license, no account required to start.
Can I save or share my simulation?▾
Create a free account to save projects, and use a shareable embed or minted DOI to publish a live, interactive version anywhere.
How accurate are the results?▾
The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.