Stars are considered to be formed by self gravitating collapse in the gas (molucular) cloud observed by emission lines of molucular CO. Let'ts simulate the process of gravitational collapse with isotropic magnetic fields.

[Initial Condition]

Let give 10% density perturvation on isotropic (constant density) gas with uniform magnetic fields in 'y' direction, and follow its evolution.

In the figure, color shows density, arrows show velocity, and lines show magnetic field lines.

[Evolved Stage]

The region where its density becomes denser than surrounding gas accumulates surrounding gas by its gravity and increases its density. The denser is the stronger of its gravity, and its evolution is accelerated. When magnetic fields exist, gas will collapse along with magnetic field and form a disk.

Density is decreasing from Red, to Orange, Olive, Green, and Aqua.