Magnetic Fields are Essential for the Star Forming Process

Though the star formation theory is well developed and very much understood, scientists found that there are some unexplained issues in it. It cannot explain a key element in the final stage of a star's birth, the link between its angular momentum or spin as it is known, and the centrifugal forces that act on its entire mass.

Stars form clouds mostly composed of molecular hydrogen, helium, dust and small amounts of other heavy elements, remnants of supernovas. The gravitational force acting on the entire mass of gas, causes it to spin faster and faster, until the gravity at its center is powerful enough to draw even more gas. This process is called gravitational collapse, in which the cloud falls on itself under its own weight.

As more and more gas is drawn into the ever growing sphere of gas, the extreme pressures at its core stirs a heating process which will trigger a thermonuclear reaction called nuclear fusion. Nuclear fusion is a process in which extreme pressure and temperature causes hydrogen atoms to smash into each other to form heavier atom nuclei, and thus new chemical elements.

Calculations and observations show that typical molecular clouds, rotating ever faster as they collapse, would never allow it to compress into a small enough volume to form a star due to the centrifugal forces acting on its mass that would overcome the gravitational pull, and thus triggering the disintegration of the protostar. It would need to lose some of its angular momentum to allow the star's birth.

A new theory, proposed by Antonio Chrysostomou and his colleagues at the University of Hertfordshire in Britain, says that excess matter and energy is shed away from the protostar along magnetic fields surrounding it, to permit the final collapse stage. The new theory has produced so far at least one verifiable prediction in the star formation system HH 135-136, in which magnetic fields that extend 50,000 astronomical units around the structure, throw matter away from the protostar at a speed of 100 kilometers per second.

Chrysostomou also predicts that as the star forming process enters its final stage, the magnetic fields around will straighten out to become like the general magnetic fields of the galaxy, but observation of our own sun shows that the field line situated close to the star will curve a little, and some would curve on its surface to create the famous solar spots.