A planetary system is a collection of planets and smaller objects, such as moons, asteroids, and comets, orbiting around a star. Planetary systems are believed to originate from rotating clouds of dust and gas that encircle stars shortly after their birth (see planetary systems, formation). Evidence is gathering that they are relatively common.
Related entry• extrasolar planets
Related categories PLANETS AND MOONS
EXTRASOLAR PLANETS AND SUBSTELLAR OBJECTS
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