Labs / Astronomy
Exoplanet Transit
A planet drifts in front of its star and the star's brightness dips — the same signal telescopes like Kepler use to find new worlds. Drag up or down over the star to tilt the orbit, or move the sliders, and watch how the depth, shape, and duration of the dip change. The depth is just the planet-to-star area ratio, so the light curve alone reveals the planet's size.
flux 100.00%depth 1.00%duration 0.0 hRp (dip) 0.0 R⊕
What to try
- The dip depth is only about 1% for a giant planet. How big does the planet have to be before the dip becomes obvious?
- Tilt the orbit until the planet just clips the star's edge. What happens to the shape of the dip when the transit is only grazing?
- Keep tilting. At what inclination does the transit vanish altogether — and what does that tell you about which planets we can and can't see this way?
- Stretch the orbital period out to 40 days. Why does the transit last longer, and how much rarer do the dips become?
- During a grazing transit, is the planet radius inferred from the dip too big, too small, or just right compared to the slider?