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n. Any of innumerable small bodies thought to have orbited the sun during the formation of the planets.

n. Any of many small, solid astronomical objects, that orbit a star and form protoplanets through mutual gravitational attraction

Of or pertaining to a minute planet or planetary body.

n. One of the minute bodies moving in planetary orbits, from time to time overtaking each other and coalescing, and so gradually building up the planets, according to the planetesimal hypothesis.

n. one of many small solid celestial bodies thought to have existed at an early stage in the development of the solar system

"The Murchison meteorite, as it is now known, is a fragment of a "planetesimal" or small, solid fragment that condensed out of the solar nebula as the solar system formed."

heavenly body    celestial body   

planetesimal hypothesis    superplanet    planet    protoplanet    planemo