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MCQAdvancedSolar System & Planetary Science
USAAAO — 2026 First Round
Question 16
Kepler-22b is an exoplanet discovered by transiting with an orbital period of 290 days. Suppose it has a mass of 4.84 × 10²⁵ kg and a moon similar to Earth’s, with a prograde orbit near the ecliptic plane of the Kepler-22 system and a semi-major axis of 7.70 × 10⁸ m. What is the length of a synodic lunar month, i.e., the time between successive full moons, for an observer on Kepler-22b? You can neglect the mass of the moon.
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Source
USAAAO 2026 First Round, Question 16. Question text, choices, and answer were transcribed from the official USAAAO exam and solutions PDFs.