1. planetesimal - Noun
2. planetesimal - Adjective
one of many small solid celestial bodies thought to have existed at an early stage in the development of the solar system
Source: WordNetAs with the Earth, the denser metal separated from silicate material and sank toward the center of the planetesimal, forming its core. Source: Internet
After the planetesimal solidified, it broke up in a collision with another planetesimal. Source: Internet
The gravitational repercussions of such a resonance ultimately destabilized the orbits of Uranus and Neptune, causing them to be scattered outward onto high-eccentricity orbits that crossed the primordial planetesimal disc. Source: Internet
Early in the Solar System's history, Mercury may have been struck by a planetesimal of approximately 1/6 that mass and several thousand kilometers across. Source: Internet
Like other members of the Kuiper belt, Pluto is thought to be a residual planetesimal ; a component of the original protoplanetary disc around the Sun that failed to fully coalesce into a full-fledged planet. Source: Internet
The remaining planets then continue their migration until the planetesimal disc in nearly depleted with small fractions remaining in various locations. Source: Internet