Search results
Results From The WOW.Com Content Network
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. [1] [2] Most astronomical objects, such as galaxies, stars, and planets, are formed by accretion processes.
In a protoplanetary disk, the probability of accretion of pebbles ranging in size from centimeters to a meter is ≤10% on planets up to about 20 Earth masses. [1] A protoplanetary disk is made up of a mix of gas and solids including dust, pebbles, planetesimals, and protoplanets. [2]
Original file (1,275 × 1,650 pixels, file size: 357 KB, MIME type: application/pdf) This is a file from the Wikimedia Commons . Information from its description page there is shown below.
Core formation utilizes several mechanisms in order to control the movement of metals into the interior of a planetary body. [3] Examples include percolation, diking, diapirism, and the direct delivery of impacts are mechanisms involved in this process. [3] The metal to silicate density difference causes percolation or the movement of a metal ...
[22] [34] The latter scenario is thought to be the most promising one, because it can explain the formation of the giant planets in relatively low-mass disks (less than 0.1 M ☉). [34] In this model giant planet formation is divided into two stages: a) accretion of a core of approximately 10 M E and b) accretion of gas from the protoplanetary ...
A group of the world's leading planet formation experts decided at a conference in 2006 [8] on the following definition of a planetesimal: A planetesimal is a solid object arising during the accumulation of orbiting bodies whose internal strength is dominated by self-gravity and whose orbital dynamics is not significantly affected by gas drag .
The orbits of the planets can converge if the migration of the inner planet is halted at the inner edge of the gas disk, resulting in a system of tightly orbiting inner planets; [33] or if migration is halted in a convergence zone where the torques driving Type I migration cancel, for example near the ice line, in a chain of more distant planets.
Core–mantle differentiation is the set of processes that took place during the accretion stage [1] of Earth's evolution (or more generally, of rocky planets) that results in the separation of iron-rich materials that eventually would conform a metal core, surrounded by a rocky mantle.