Circular orbit (e≈0 — true for hot Jupiters) · M_planet ≪ M_star · box-shaped transit with linear ingress (no limb darkening) · dataset simplified from CHEOPS for teaching (real published depth ≈0.67%; here 0.9% for cleaner numbers). Internally 100% self-consistent.

Hot Jupiter around a bright F-star. High signal-to-noise — the perfect first case for a detective.

Hover/touch the light curve to read exact values — it's an instrument, not a picture. Each phase opens with a 🧠 reasoning question that unlocks the calculator work: think first, compute second. Enter submits · H hint · R restart. Wrong submissions cost −2 pts.

Each phase: answer the reasoning question, then compute and commit a number. Medal by accuracy — 🥇 under 5% · 🥈 under 10% · 🥉 under 20% error — and finishing a phase unlocks the next. A wrong answer costs −2 points (−1 on Easy, and your first reasoning slip on each question is free on Easy). A hint costs −3/−4/−5. Easy also shows worked scaffolds. Fewer tries + higher accuracy = higher score — so calculate, don’t guess.