Mechanism by which the collapse of interstellar gas clouds causes star formation
Star formation
Object classes
Interstellar medium
Molecular cloud
Bok globule
Dark nebula
Young stellar object
Protostar
Pre-main-sequence star
T Tauri star
Herbig Ae/Be star
Herbig–Haro object
Theoretical concepts
Accretion
Initial mass function
Jeans instability
Kelvin–Helmholtz mechanism
Nebular hypothesis
Planetary migration
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The Jeans instability is a concept in astrophysics that describes an instability that leads to the gravitational collapse of a cloud of gas or dust.[1] It causes the collapse of interstellar gas clouds and subsequent star formation. It occurs when the internal gas pressure is not strong enough to prevent the gravitational collapse of a region filled with matter.[2] It is named after James Jeans.
For stability, the cloud must be in hydrostatic equilibrium, which in case of a spherical cloud translates to
where is the enclosed mass, is the pressure, is the density of the gas (at radius ), is the gravitational constant, and is the radius. The equilibrium is stable if small perturbations are damped and unstable if they are amplified. In general, the cloud is unstable if it is either very massive at a given temperature or very cool at a given mass; under these circumstances, the gas pressure gradient cannot overcome gravitational force, and the cloud will collapse,[3] is called Jeans collapse criterion.
The Jeans instability likely determines when star formation occurs in molecular clouds.
^"Jeans instability". Oxford Reference. Retrieved 2024-01-05.
^Bonnor, W. B. (1957). "1957MNRAS.117..104B Page 104". Monthly Notices of the Royal Astronomical Society. 117: 104. Bibcode:1957MNRAS.117..104B. doi:10.1093/mnras/117.1.104. Retrieved 2024-01-05.
The Jeansinstability is a concept in astrophysics that describes an instability that leads to the gravitational collapse of a cloud of gas or dust. It...
equation, called Jeans mass or Jeansinstability, that solves for the critical mass a cloud must attain before being able to collapse. Jeans also helped to...
the 1920s. They are parallel in form to Jeansinstability waves, which are caused by gravitational instabilities in a static medium. Consider an electrically...
inward gravitational forces generated by the same particles (see Jeansinstability and Bonnor–Ebert mass). This causes the cloud to wobble or oscillate...
of Thomas Chamberlin and Forest Moulton (1901), the tidal model of James Jeans (1917), the accretion model of Otto Schmidt (1944), the protoplanet theory...
reaches a sufficient density of matter to satisfy the criteria for Jeansinstability, it begins to collapse under its own gravitational force. As the cloud...
and instabilities causing the matter to be crushed inwards under its own gravity. This instability was clarified in 1902 by the Jeansinstability criterion...
formation because it feels only the force of gravity: the gravitational Jeansinstability which allows compact structures to form is not opposed by any force...
mass density increases. Since the criteria for cloud collapse (the Jeansinstability) depends on density, a higher density makes it more likely for clouds...
cartwheel's “spokes”. Alternatively, a model based on the gravitational Jeansinstability of both axisymmetric (radial) and nonaxisymmetric (spiral) small-amplitude...
relation. Thus, a too-high or too-low temperature will result in stellar instability. A better approximation is to take ε = L/M, the energy generation rate...
suggested by astronomers. Cloud growth by collision and gravitational instability in the gas layer spread throughout the galaxy. Models for the collision...
the sheet is unstable. The firehose instability is precisely complementary, in this sense, to the Jeansinstability in the plane, which is stabilized at...
hydrodynamic and plasma instabilities named after people (eponymous instabilities). Eponym List of fluid flows named after people Instability Hydrodynamic stability...
(2007). "Origin of the structure of the Kuiper Belt during a dynamical instability in the orbits of Uranus and Neptune". Icarus. 196 (1): 258. arXiv:0712...
Higher ambient temperature increases the mass of collapsing gas clouds (Jeans mass); lower gas metallicity reduces the radiation pressure thus make the...
formation. This effect is also known as the Jeansinstability, after the British physicist James Hopwood Jeans who published it in 1902. The original formulation...
(August 2005). "The photometric evolution of FU Orionis objects: disc instability and wind–envelope interaction". Monthly Notices of the Royal Astronomical...
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