Jeans instability

Jeans instability can also give rise to fragmentation in certain conditions.

The Jeans instability likely determines when star formation occurs in molecular clouds.

Jeans instability is a physical state in which an interstellar cloud of gas will begin to undergo collapse and form stars.

This instability was clarified in 1902 by the Jeans instability criterion.

In physics, the Jeans instability causes the collapse of interstellar gas clouds and subsequent star formation.

Once a region reaches a sufficient density of matter to satisfy the criteria for Jeans instability, it begins to collapse under its own gravitational force.

They are parallel in form to Jeans instability waves, which are caused by gravitational instabilities in a static medium.

Since the criteria for cloud collapse (the Jeans instability) depends on density, a higher density makes it more likely for clouds to collapse and form stars.

The firehose instability is precisely complementary, in this sense, to the Jeans instability in the plane, which is stabilized at short wavelengths, .

Ordinary baryonic matter had too high a temperature, and too much pressure left over from the Big Bang to collapse and form smaller structures, such as stars, via the Jeans instability.

Jeans came up with another version of this equation, called Jeans mass or Jeans instability, that solves for the critical mass a cloud must attain before being able to collapse.

Dark matter plays a key role in structure formation because it feels only the force of gravity: the gravitational Jeans instability which allows compact structures to form is not opposed by any force, such as radiation pressure.

If not disrupted by external forces, the stability of dust clouds is a fine balance between outward pressure caused by the heat or pressure of the cloud's contents, and inward gravitational forces generated by the same particles (see Jeans instability and Bonnor-Ebert mass).

Alternatively, a model based on the gravitational Jeans instability of both axisymmetric (radial) and nonaxisymmetric (spiral) small-amplitude gravity perturbations allows an association between growing clumps of matter and the gravitationally unstable axisymmetric and nonaxisymmetric waves which take on the appearance of a ring and spokes.