What is planetesimal accretion?
planetesimal hypothesis: building blocks of solid planets are km-sized rocky/icy “planetesimals” that are formed by coagulation of dust grains in the disk, core accretion model: gas components of gas giants are added after rocky/icy planets (cores) accrete from the planetesimals.
What are planetesimals protoplanets?
Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other’s orbits and collide, gradually coalescing into the dominant planets. In the case of the Solar System, it is thought that the collisions of planetesimals created a few hundred planetary embryos.
What is planetesimal bombardment?
There may have been a dramatic event early in the history of the Solar System–the intense bombardment of the inner planets and the Moon by planetesimals during a narrow interval between 3.92 and 3.85 billion years ago, called the late heavy bombardment, but also nicknamed the lunar cataclysm.
How do protoplanets grow?
A protoplanet is a massive object that will eventually become a planet. Protoplanets grew around our protosun, an early stage in the formation of our sun, by capturing solid material. As they got bigger, they were heated in two ways. One way is known as heat of formation.
What is planetesimal and tidal theory?
The tidal theory, proposed by James Jeans and Harold Jeffreys in 1918, is a variation of the planetesimal concept: it suggests that a huge tidal wave, raised on the sun by a passing star, was drawn into a long filament and became detached from the principal mass.
What forms planetesimals which form protoplanets?
Condensation
Lesson Summary Condensation, the process of forming solid particles from the solar nebula, is an early process in the formation of a planetesimal, an early solar system body of small to medium size that combines with other planetesimals to form protoplanets.
What is the first step in planetesimal formation?
These bodies are known as planetesimals. They form initially from small fragments of solar dust and chondrules by the processes of cohesion (sticking together by weak electrostatic forces) and by gravitational instability. Cohesion forms fragments up to about 1 cm in diameter.
How do protoplanets form?
Protoplanets are built up through the collisions of planetesimals over millions of years. The protoplanets orbit stably around the Sun for a while, but eventually they collide with each other. In about 100 million years, several terrestrial planets, like the ones found in our Solar System, are formed.
How is planetesimal formed?
Planetesimals formed in the solar nebula by collisional coagulation. Dust aggregates settled toward the central plane, the larger ones growing by sweeping up smaller ones.