Accretion

Definition

Accretion is the process by which particles in space stick together to form larger bodies, such as planets and stars. This occurs through collisions and gravitational attraction, leading to the growth of celestial objects.

5 Must Know Facts For Your Next Test

1. Accretion plays a crucial role in the formation of planetesimals, the building blocks of planets.
2. Gravitational forces help small particles come together and eventually form larger bodies during accretion.
3. Accretion disks around young stars are regions where material accumulates and may form planets.
4. The process of accretion can lead to significant heating, which affects the physical properties of forming celestial bodies.
5. Accretion is not only important in planetary formation but also in the growth of moons, asteroids, and comets.

Review Questions

• What role does gravity play in the process of accretion?
• How does accretion contribute to the formation of planetesimals?
• Why are accretion disks significant in planetary formation?

Related terms

Planetesimal: A small body formed from dust and gas during the early stages of planetary formation.

Protoplanetary Disk: A rotating disk of dense gas and dust surrounding a newly formed star, within which planets may form.

Gravitational Collapse: The contraction of an astronomical object due to its own gravity, often leading to the formation of stars or black holes.