Astrophysics (index)


(objects held together by gravity that combine to form planets)

Planetesimal is a term used in the currently accepted model of Planet Formation: the combining of Cosmic Dust into small objects, with additional combination leading to planets. When the object is large enough to be held together by its own Gravity, it is termed a planetesimal. In the solar system this would be an object roughly at least 1 km diameter. It is also assumed that its motion is dominated by a gravitational orbit rather than by the influence of gas it is passing through.

The term has also been used for objects in the solar system of similar size including Comets and Asteroids.

(object type)

Referenced by:
Circumstellar Disk
Isolation Mass
Kilometer Size Barrier
Planetary Migration
Planet Formation
Protoplanetary Disk