Solar System/Planet Formation and Structure: Difference between revisions
Briefly summarized Core Accretion and Disk Instability |
added more info to disk instability |
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The 2 main/most common theories for planet formation are disk instability and core accretion. | The 2 main/most common theories for planet formation are disk instability and core accretion. | ||
== Core Accretion == | |||
Core Accretion is the theory that planets form from small particles gathering together and forming lumps that accumulate more and more mass. This process is slow, taking millions of years. | Core Accretion is the theory that planets form from small particles gathering together and forming lumps that accumulate more and more mass. This process is slow, taking millions of years. | ||
== Disk Instability == | |||
Disk Instability is the theory that planets form from spinning disks of material that accumulates so much mass, it violently collapses on itself and forms a planet. This is a quick process, taking just thousands of years. | Disk Instability is the theory that planets form from spinning disks of material that accumulates so much mass, it violently collapses on itself and forms a planet. This is a quick process (speaking relatively), taking just thousands of years. | ||
=== Toomre-Q Parameter === | |||
The Toomre Q-parameter is a dimensionless quantity used in astrophysics to measure the gravitational stability of a rotating disk of gas or stars (such as a galaxy or protoplanetary disk). It determines whether a disk will remain stable or fragment into smaller clumps due to its own gravity. | |||
[[File:Toomre-Q Parameter Equation.png|alt=Q = (speed of sound * rotational shear) / pi * gravitational constant * surface density|thumb|The equation in question]] | |||
'''Stability Thresholds-''' | |||
Q > 1 : Disk is stable | |||
Q < 1 : Disk is unstable | |||
Q ≈ 1 : Disk is marginally stable | |||
Latest revision as of 02:44, 9 January 2026
Core Accretion and Disk Instability
The 2 main/most common theories for planet formation are disk instability and core accretion.
Core Accretion
Core Accretion is the theory that planets form from small particles gathering together and forming lumps that accumulate more and more mass. This process is slow, taking millions of years.
Disk Instability
Disk Instability is the theory that planets form from spinning disks of material that accumulates so much mass, it violently collapses on itself and forms a planet. This is a quick process (speaking relatively), taking just thousands of years.
Toomre-Q Parameter
The Toomre Q-parameter is a dimensionless quantity used in astrophysics to measure the gravitational stability of a rotating disk of gas or stars (such as a galaxy or protoplanetary disk). It determines whether a disk will remain stable or fragment into smaller clumps due to its own gravity.
Stability Thresholds-
Q > 1 : Disk is stable
Q < 1 : Disk is unstable
Q ≈ 1 : Disk is marginally stable