Csillagképzés

Csillagképzés, meaning "star formation" in Hungarian, refers to the process by which dense regions within molecular clouds in interstellar space collapse under their own gravity to form stars. These molecular clouds are vast, cold, and dark reservoirs of gas and dust, primarily composed of molecular hydrogen and helium, with trace amounts of heavier elements and dust grains.

The process begins when a disturbance, such as a shockwave from a nearby supernova or a collision between molecular clouds, triggers a gravitational instability within a portion of the cloud. This instability causes the region to fragment and condense. As the material collapses, it spins faster due to the conservation of angular momentum, and a protostar forms at the center. This protostar is surrounded by a rotating disk of gas and dust, known as a protoplanetary disk, from which planets may eventually form.

The protostar continues to accrete mass from the surrounding disk, increasing its temperature and pressure. Eventually, the core becomes hot and dense enough for nuclear fusion to ignite, where hydrogen atoms fuse to form helium, releasing vast amounts of energy. This marks the birth of a star. The outward pressure from the fusion process balances the inward pull of gravity, stabilizing the star. Stars typically spend the majority of their lives in this stable, hydrogen-burning phase, known as the main sequence. The entire process of star formation can take millions of years.